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{{Short description|none}}
{{hatnote|"1,000", "Thousand", and "Chiliad" redirect here. For other uses, see 1000 (disambiguation) or, for the military unit, see Chiliarchy.}}
{{Infobox number
| number        = 1000
| divisor       = 1, 2, 4, 5, 8, 10, 20, 25, 40, 50, 100, 125, 200, 250, 500, 1000
| roman unicode = M, m, ↀ
| unicode       = ↀ
| Greek prefix  = chilia
| Latin prefix  = milli
| lang1         = [[Tamil numerals|Tamil]]
| lang1 symbol  = ௲
| lang2         = [[Chinese numerals#Standard numbers|Chinese]]
| lang2 symbol  = 千
| lang3         = [[Social:Punjabi language|Punjabi]]
| lang3 symbol  = ੧੦੦੦
|lang4         = [[Devanagari numerals#Standard numbers|Devanagari]]
| lang4 symbol = १०००
}}

'''1000''' or '''one thousand''' is the [[Natural number|natural number]] following [[999 (number)|999]] and preceding [[1001 (number)|1001]]. In most English-speaking countries, it can be written with or without a comma or sometimes a period separating the thousands digit: '''1,000'''.

A group of one thousand things is sometimes known, from Ancient Greek, as a '''chiliad'''.<ref>{{Cite web|url=https://www.merriam-webster.com/dictionary/chiliad|title=chiliad|publisher=Merriam-Webster | archive-url=https://archive.today/20220325170822/https://www.merriam-webster.com/dictionary/chiliad|archive-date=March 25, 2022|url-status=live}}</ref> A period of one thousand years may be known as a chiliad or, more often from [[Social:Latin language|Latin]], as a [[Millennium|millennium]]. The number 1000 is also sometimes described as a '''short thousand''' in medieval contexts where it is necessary to distinguish the Germanic concept of 1200 as a [[Long thousand|long thousand]].

== Notation ==

* The decimal representation for one thousand is
** '''1000'''—a one followed by three zeros, in the general notation;
** '''1 × 10<sup>3</sup>'''—in [[Engineering:Engineering notation|engineering notation]], which for this number coincides with:
** '''1 × 10<sup>3</sup>''' exactly—in [[Scientific notation|scientific normalized exponential notation]];
** '''1 E+3''' exactly—in [[Scientific notation#E notation|scientific E notation]].
* The [[SI prefix]] for a thousand units is "[[Kilo-|kilo-]]", abbreviated to "k"—for instance, a [[Kilogram|kilogram]] or "kg" is a thousand [[Gram|gram]]s. This is sometimes extended to non-SI contexts, such as "ka" (kiloannum) being used as a shorthand for periods of 1000 years. In [[Computer science|computer science]], however, "kilo-" is used more loosely to mean 2 to the 10th power (1024).
* In the SI writing style, a non-breaking space can be used as a thousands separator, i.e., to separate the digits of a number at every power of 1000.
* Multiples of thousands are occasionally represented by replacing their last three zeros with the letter "K" or "k": for instance, writing "$30k" for $30&nbsp;000 or denoting the [[Year 2000 problem|Y2K]] computer bug of the year 2000.
* A thousand units of [[Finance:Currency|currency]], especially dollars or pounds, are colloquially called a ''grand''. In the United States, this is sometimes abbreviated with a "G" suffix.

== Properties ==
1000 is the 10th [[Icositetragon|icositetragon]]al number, or 24-gonal number.<ref>{{Cite OEIS |A051876 |24-gonal numbers. |access-date=2022-11-30 }}</ref> It is also the 16th generalized 30-gonal number.<ref>{{Cite OEIS |A316729 |Generalized 30-gonal (or triacontagonal) numbers: m*(14*m - 13) with m equal to 0, +1, -1, +2, -2, +3, -3, ... |access-date=2024-01-21 }}</ref>

1000 is the [[Wiener index]] of [[Cycle (graph theory)|cycle]] length [[20 (number)|20]], also the sum of labeled boxes arranged as a [[Pyramid (geometry)|pyramid]] with base 1 – 20.<ref>{{Cite OEIS |A034828 |a(n) equal to floor(n^2/4)*(n/2). |access-date=2024-01-21 }}</ref><ref>{{Cite web |author=Ngaokrajang, Kival |editor=Sloane, N. J. A. |title=Illustration for n equal to 1..10 [A034828]. |url=https://oeis.org/A034828/a034828.jpg |website=The [[On-Line Encyclopedia of Integer Sequences]] |publisher=OEIS Foundation }}</ref><ref>{{Cite arxiv |last1=Janjic |first1=M. |last2=Petkovic |first2=B. |title=A Counting Function |year=2013 |pages=14,15 |eprint=1301.4550 |class=math.CO }} {{bibcode|2013arXiv1301.4550J}}</ref>{{efn|1=1000 is the fourth Wiener index of the grid <math>P_{4} \times P_{4}</math> where <math>P_{4}</math> is the [[Path graph|path graph]] on four vertices.<ref>{{Cite OEIS |A143945 |Wiener index of the grid P_n x P_n, where P_n is the path graph on n vertices. |access-date=2024-01-21 }}</ref> A connected graph with a given [[Wiener index]] represents the sum of the distances between all [[Unordered pair|unordered pair]]s of [[Vertex (graph theory)|vertices]] in said graph. }}

1000 is the element of [[Multiplicity (mathematics)|multiplicity]] in a <math>24 \times 24</math> toroidal board in the [[Eight queens puzzle#Related problems|''n''-Queens problem]],<ref>{{Cite OEIS |A054501 |Multiplicity sequence for classification of nonattacking queens on n X n toroidal board. |access-date=2024-01-21 }}</ref> with respective [[Indicator function|indicator]] of [[25 (number)|25]]<ref>{{Cite OEIS |A054500 |Indicator sequence for classification of nonattacking queens on n X n toroidal board. |access-date=2024-01-21 }}</ref> and [[Counting#Counting in mathematics|count]] of [[51 (number)|51]].<ref>{{Cite OEIS |A054502 |Counting sequence for classification of nonattacking queens on n X n toroidal board. |access-date=2024-01-21 }}</ref><ref>I. Rivin, I. Vardi and P. Zimmermann (1994). [https://www.jstor.org/stable/2974691 The n-queens problem.] [[American Mathematical Monthly]]. Washington, D.C.: Mathematical Association of America. '''101''' (7): 629–639. {{doi|10.1080/00029890.1994.11997004}} {{jstor|2974691}}</ref>

1000 is the number of [[Partition function (number theory)|strict partitions]] of [[50 (number)|50]] containing the sum of no [[Subset|subset]] of the [[Partition (number theory)|parts]].<ref>{{Cite OEIS |A364349 |Number of strict integer partitions of n containing the sum of no subset of the parts. |access-date=2024-01-21 }}</ref>

[[File:Star polygon 1000-499.svg|300px|thumb|The regular polygram {1000/499} of the [[Chiliagon|chiliagon]], where its [[Diagonal|diagonal]]s do not pass through the [[Centre (geometry)|center]], yet are closest to it (indistinguishably, unless one zooms in).]]

A '''[[Chiliagon|chiliagon]]''' is a 1000-sided [[Polygon|polygon]],<ref name="Chilia">{{Cite OEIS |A195163 |1000-gonal numbers: a(n) equal to n*(499*n - 498). |access-date=2024-01-21 }}</ref><ref>{{Cite journal |last=Aṣiru |first=Muniru A. |title=All square chiliagonal numbers |journal=International Journal of Mathematical Education in Science and Technology |volume=47 |issue=7 |publisher=Taylor & Francis |location=Oxfordshire |year=2016 |pages=1123–1134. |doi=10.1080/0020739X.2016.1164346 |bibcode=2016IJMES..47.1123A |mr=3528540 |zbl=1396.97005 |s2cid=123953958 }}</ref> of order [[2000 (number)|2000]] in its [[Regular polygon|regular form]].{{efn|1=In the sequence of regular '''1000'''-gonal numbers of the form <math>n \times (499n - 498)</math>, the first non-trivial solution is 2997.<ref name="Chilia" /> In Chowla's function, that counts the sum of divisors except for <math>1</math> and <math>n</math>, 2997 is the first number to have a value of 1600,<ref>{{Cite OEIS |A048050 |Chowla's function: sum of divisors of n except for 1 and n. |access-date=2024-01-21 }}</ref> which is the Euler totient of [[4000 (number)|4000]] and [[6000 (number)|6000]],<ref name="ETot" /> while the fifth member in the sequence 9985 (that follows 0, 1, 1000, 2997 and 5992)<ref name="Chilia" /> has an [[Arithmetic number|average of divisors]] that is 2997;<ref>{{Cite OEIS |A003601 |Numbers n such that the average of the divisors of n is an integer: sigma_0(n) divides sigma_1(n). |access-date=2023-07-16 }}</ref><ref>{{Cite OEIS |A102187 |Arithmetic means of divisors of arithmetic numbers (arithmetic numbers, A003601, are those for which the average of the divisors is an integer). |access-date=2023-07-16 }}</ref> with 5992 '''÷''' 2 = 2996, and 1000 + 2997 + 5992 = 9989 (a difference of 4 from the fourth member, after 1).<br />There are 499 regular star polygrams to the regular chiliagon: [[300 (number)|300]] are regular [[Polygram (geometry)#Regular compound polygons|compound star forms]] — a count that represents the twenty-fourth [[Triangular number|triangular number]]<ref>{{Cite OEIS |A000217 |Triangular numbers: a(n) is the binomial(n+1,2): n*(n+1)/2 equal to 0 + 1 + 2 + ... + n. |access-date=2024-01-21 }}</ref> — with the remaining 199 forms represented by simple regular [[Polygram (geometry)#Generalized regular polygons|star polygons]]. }}

=== Totient values ===

1000 has a [[Carmichael function|reduced totient]] value <math>\lambda(n)</math> of [[100 (number)|100]],<ref>{{Cite OEIS |A002322 |Reduced totient function psi(n): least k such that x^k is congruent 1 (mod n) for all x prime to n; also known as the Carmichael lambda function (exponent of unit group mod n); also called the universal exponent of n. |access-date=2023-12-18 }}</ref> and [[Euler's totient function|Euler totient]] <math>\varphi(n)</math> of [[400 (number)|400]].<ref name="ETot">{{Cite OEIS |A000010 |Euler totient function phi(n): count numbers less than or equal to n and prime to n. |access-date=2023-12-18 }}</ref> 

[[11 (number)|11]] integers have a [[Euler's totient function|totient]] value of 1000 (1111, 1255, ...,  3750).<ref name="ETot" />

One thousand is also equal to the sum of [[Totient summatory function|Euler's totient summatory function]] <math>\Phi(n)</math> over the first [[57 (number)|57]] integers.<ref>{{Cite OEIS |A002088 |Sum of totient function: a(n) is Sum_{k equal to1..n} phi(k), cf. A000010. |access-date=2023-12-18 }}</ref> 

====Repdigits====

In [[Decimal|decimal]], [[Multiple (mathematics)|multiples]] of one thousand are '''totient''' values of four-digit [[Repdigit|repdigit]]s:<ref name="ETot" />
{{Bullet list
|[[7000 (number)#7700 to 7799|7777]] and [[9999 (number)|9999]] have totients of [[6000 (number)|6000]],
|5555, and [[8000 (number)#8800 to 8899|8888]] (as well as 11110) have totients of [[4000 (number)|4000]],
|3333, 4444 and [[6000 (number)#6600 to 6699|6666]] have totients of [[2000 (number)|2000]],
|1111 and [[2000 (number)#2200 to 2299|2222]] have a totient of 1000.
}}

Notice, that in the [[Composite number|list of composite numbers]], 7777 is very nearly the composite [[Sequence|index]] of 8888: 8886 is the 7779th composite number.<ref name="CompN">{{Cite OEIS |A002808 |The composite numbers: numbers n of the form x*y for x > 1 and y > 1. |access-date=2023-12-18 }}</ref> Also,<ref name="ETot" /> 

{{Bullet list
|[[5000 (number)|5000]] has a totient value of 2000, as does 5050 {{=}} 2025 + [[3000 (number)#3001 to 3099|3025]] {{=}} [[45 (number)|45]]<sup>2</sup> + [[55 (number)|55]]<sup>2</sup>, where
|[[3000 (number)|3000]], 5000 and [[7000 (number)|7000]] are the three multiples of one thousand, less than 10<sup>4</sup>, to not be totient values of four-digit repdigits;
|'''10000''' has a totient value of 4000. The totient of 1000 is 400, of 100 it is 40, and of 10 it is [[4|4]].

}}

1600 = [[40 (number)|40]]<sup>2</sup> is the totient value of 4000, as well as 6000, whose collective sum is 10000, where 6000 is the totient of 9999, one less than 10<sup>4</sup>.<ref name="ETot" />{{efn|1='''1600''', a repdigit in septenary (4444<sub>7</sub>),<ref>{{Cite OEIS |A048332 |Numbers that are repdigits in base 7. |access-date=2023-12-21 }}</ref> is the composite index of 1891, in turn the like-index of 2223.<ref name="CompN" /><br /> 2222 and 8888 are both numbers {{math|1=''n'' }} such that {{math|1=''n'' − 1}} is prime (as with 4, 44, 444, and 888),<ref>{{Cite OEIS |A028987 |Repdigit - 1 is prime. |access-date=2023-12-21 }}</ref> yielding respectively the 331st and 1107th prime numbers,<ref name="PNum" /> where the former (2221) is also the 64th [[Super-prime|super-prime]].<ref name="SupP">{{Cite OEIS |A006450 |Prime-indexed primes: primes with prime subscripts. |access-date=2023-12-19 }}</ref> These two prime indexes collectively have a [[Interval (mathematics)#Definitions and terminology|range]] of [[777 (number)|777]] integers (1107{{hair space}}''':'''{{hair space}}331), which as a number is also a repdigit in [[Senary|senary]].<ref>{{Cite OEIS |A048331 |Numbers that are repdigits in base 6. |access-date=2023-12-21 }}</ref> }}

The sum of the first nine prime numbers up to [[23 (number)|23]] is 100, with <math>\varphi(p(23)) = 1000</math>, where <math>p(23) = 1255</math> is the number of [[Partition (number theory)|integer partitions]] of 23.<ref>{{Cite OEIS |A366581 |a(n) equal to phi(p(n)), where phi is Euler's totient function (A000010) and p(n) is the number of partitions of n (A000041). |access-date=2023-12-18 }}</ref>

=== Prime values ===

Using decimal representation as well, 
{{Bullet list
|997 is the 168th and largest prime number less than '''1000''',<ref name="PNum">{{Cite OEIS |A000040 |The prime numbers. |access-date=2023-12-19 }}</ref> while
|[[97 (number)|97]] is the 25th and largest prime number less than '''[[100|100]]'''; with
|[[9|9]] and [[7|7]] respectively the (4th) largest composite and prime less than '''[[10|10]]'''.<ref name="CompN"/><ref name="PNum" />
}}

On the other hand, the largest prime number less than 10000 is the 1229th prime number, [[9000 (number)#9900 to 9999|9973]].<ref name="PNum" />{{efn|1=The sum {{math|1=('''[[2|2]]''' + [[3|3]] + [[5|5]] + '''...''' + '''[[29 (number)|29]]''') }} of the first 10 prime numbers is [[129 (number)|129]], which is the 97th indexed [[Composite number|composite number]].<ref>{{Cite OEIS |A127337 |Numbers that are the sum of 10 consecutive primes. |access-date=2023-12-18 }}</ref><ref name="CompN" /> 9973 is also the 201st ''super-prime'',<ref name="SupP" /> where {{math|1=1000 − [[201 (number)|201]] = 799 }}, which is the smallest number in decimal to have a [[Digit sum|digit sum]] of 25,<ref>{{cite OEIS |A051885 |Smallest number whose sum of digits is n. |access-date=2023-12-20}}</ref> and the ''mirror'' permutation of digits of 997.<br />When splitting four-digit 9973 into two two-digit numbers, [[99 (number)|99]] and [[73 (number)|73]], the latter is the composite index of 99, that, when added together is [[172 (number)|172]], the one hundred and thirty-second composite, with [[132 (number)|132]] itself the 99th composite;<ref name="CompN" /> 73 is the twenty-first prime number.<ref name="PNum" /><br />[[1000 (number)#1600 to 1699|1601]] is the 252nd prime,<ref name="PNum" /> itself a value with a composite index of [[197 (number)|197]],<ref name="CompN" /> where 1601 is the 40th and largest consecutive prime ''[[Lucky numbers of Euler|lucky number of Euler]]'' of the form {{math|1=''n''<sup>2</sup> + ''n'' + 41 }}.<ref>{{Cite OEIS |A202018 |a(n) equal to n^2 + n + 41. |access-date=2023-12-22 }}</ref><ref>{{Cite OEIS |A005846 |Primes of the form n^2 + n + 41. |access-date=2023-12-22 }}</ref> The number of 4-digit prime numbers, in decimal, is its mirror permutation of digits '''[[1000 (number)#1600 to 1699|1061]]''', the 172nd prime.<ref>{{Cite OEIS |A006879 |Number of primes with n digits. |access-date=2023-12-21 }}</ref><br />Also, 7, 97 and 997 are all three respectively at a difference of [[3|3]] from 10, 100 and 1000, where, on the other hand, 9973 is {{math|1=[[27 (number)|27]] = 3<sup>3</sup> }} away from 10000.<br />Note, that '''[[8|8]]''' as a [[Binary number|binary number]] is "1000",<ref>{{Cite OEIS |A007088 |The binary numbers (or binary words, or binary vectors, or binary expansion of n): numbers written in base 2. |access-date=2023-12-21 }}</ref> and this representation, when written in factorial base, is equivalent to 24<sub>10</sub>.<ref>{{Cite OEIS |A007623 |Integers written in factorial base. |access-date=2023-12-21 }}</ref> In [[Primorial|primorial base]], it is equal to 30<sub>10</sub>.<ref>{{Cite OEIS |A049345 |n written in primorial base. |access-date=2024-01-21 }}</ref>}}

1000 is also the smallest number in ''base-ten'' that generates three primes in the fastest way possible by [[Concatenation#Recreational mathematics|concatenation]] with decremented numbers:<ref>{{cite web|url=https://primes.utm.edu/curios/page.php/1000.html|title=1000|publisher=Prime Curious!|archive-url=https://archive.today/20220325171202/https://www.gcflcm.com/factors-of-1000|archive-date=March 25, 2022|url-status=live}}</ref>
{{Bulletlist
|1,000,999
|1,000,999,998,997
|1,000,999,998,997,996,995,994,993
}}
all represent prime numbers.<ref>{{Cite OEIS |A152396 |Let f(M,k) denote the decimal concatenation of k numbers starting with M: M <nowiki>|</nowiki> M-1 <nowiki>|</nowiki> M-2 <nowiki>|</nowiki> ... <nowiki>|</nowiki> M-k+1, k greater than 1. Then a(n) is the smallest M such that for all m in {1,..,n} an m-th prime occurs as f(M,k) for the smallest possible k, order prioritized m equal to 1 through n. |access-date=2023-12-22 }}</ref><ref>{{Cite OEIS |A227949 |Primes obtained by concatenating decremented numbers starting at a power of 10. |access-date=2023-12-22 }}</ref>

The ''one-thousandth'' prime number is '''[[7000 (number)#7900 to 7999|7919]]'''. It is a difference of '''1''' from the [[Order (group theory)|order]] of the smallest [[Sporadic group|sporadic group]]: <math>|\mathrm {M}_{11}| = 7920</math>.<ref>{{Cite book |last1=Ronan |first1=Mark |title=Symmetry and the Monster: One of the Greatest Quests of Mathematics |publisher=[[Organization:Oxford University Press|Oxford University Press]] |location=New York |year=2006 |pages=vii, 1–255 |isbn=978-0-19-280722-9 |oclc=180766312  |doi=10.1007/s00283-008-9007-9 |doi-access=free |mr=2215662 |zbl=1113.00002 }}</ref><ref>{{Cite OEIS |A001228 |Orders of sporadic simple groups. |access-date=2023-12-18 }}</ref>

== Numbers in the range 1001–1999 ==

=== 1001 to 1099 ===

:'''[[1001 (number)|1001]]''' = [[Sphenic number|sphenic number]] (7 × 11 × 13), pentagonal number, pentatope number, [[Palindromic number|palindromic number]]
:'''1002''' = sphenic number, [[Mertens function]] zero, [[Abundant number|abundant number]], number of [[Partition function (number theory)|partitions]] of 22
: '''1003''' = the product of some prime ''p'' and the ''p''<sup>th</sup> prime, namely ''p'' = 17.
:'''1004''' = heptanacci number<ref name="Heptanacci numbers">{{Cite OEIS|A122189|Heptanacci numbers|access-date=2017-07-13}}</ref>
:'''1005''' = Mertens function zero, decagonal pyramidal number<ref>{{cite OEIS|A007585|10-gonal (or decagonal) pyramidal numbers|access-date=2022-05-24}}</ref>
:'''1006''' = [[Semiprime|semiprime]], product of two distinct isolated primes (2 and 503); [[Unusual number|unusual number]]; square-free number; number of [[Composition (combinatorics)|composition]]s (ordered [[Partition (number theory)|partition]]s) of 22 into squares; sum of two distinct pentatope numbers (5 and 1001); number of undirected [[Hamiltonian path]]s in 4 by 5 square grid graph;<ref>{{cite OEIS|A332307|Array read by antidiagonals: T(m,n) is the number of (undirected) Hamiltonian paths in the m X n grid graph|access-date=2023-01-08}}</ref> record gap between [[Twin prime|twin prime]]s;<ref>{{cite OEIS|A036063|Increasing gaps among twin primes: size|access-date=2023-01-08}}</ref> number that is the sum of 7 positive 5th powers.<ref name="auto9">{{Cite OEIS|A003352|Numbers that are the sum of 7 positive 5th powers|access-date=2023-10-10}}</ref> In decimal: [[Equidigital number|equidigital number]]; when turned around, the number looks like a prime, 9001; its [[Cube (algebra)|cube]] can be concatenated from other cubes, 1_0_1_8_1_0_8_216 ("_" indicates concatenation, 0 = 0<sup>3</sup>, 1 = 1<sup>3</sup>, 8 = 2<sup>3</sup>, 216 = 6<sup>3</sup>)<ref>{{cite OEIS|A061341|A061341 Numbers not ending in 0 whose cubes are concatenations of other cubes|access-date=2023-01-08}}</ref>
:'''1007''' = number that is the sum of 8 positive 5th powers<ref>{{Cite OEIS|A003353|Numbers that are the sum of 8 positive 5th powers|access-date=2023-10-10}}</ref>
:'''1008''' = divisible by the number of primes below it
:'''1009''' = smallest four-digit [[Prime number|prime]], [[Palindromic number|palindromic]] in bases 11, 15, 19, 24 and 28: (838<sub>11</sub>, 474<sub>15</sub>, 2F2<sub>19</sub>, 1I1<sub>24</sub>, 181<sub>28</sub>). It is also a [[Lucky prime#Lucky primes|Lucky prime]] and [[Chen prime]].
:'''1010''' = 10<sup>3</sup> + 10,<ref>{{cite OEIS|A034262|name=a(n) = n^3 + n|access-date=2022-05-24}}</ref> Mertens function zero
:'''1011''' = the largest ''n'' such that 2<sup>n</sup> contains 101 and does not contain 11011, [[Harshad number]] in bases 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75 (and 202 other bases), number of partitions of 1 into reciprocals of positive integers <= 16 [[Egyptian fraction]]<ref name="A020473">{{cite OEIS|A020473|Egyptian fractions: number of partitions of 1 into reciprocals of positive integers < n+1|access-date=2022-05-24}}</ref>
:'''1012''' = [[Ternary numeral system|ternary]] number, (32<sub>10</sub>) quadruple [[Triangular number|triangular number]] ([[Triangular number|triangular number]] is [[253 (number)|253]]),<ref>{{Cite OEIS|A046092|name=4 times triangular numbers: a(n) = 2*n*(n+1)|access-date=2023-10-10}}</ref> number of partitions of 1 into reciprocals of positive integers <= 17 [[Egyptian fraction]]<ref name="A020473" />
:'''1013''' = Sophie Germain prime,<ref name="Sophie Germain">{{Cite OEIS|A005384|Sophie Germain primes p: 2p+1 is also prime|access-date=2016-06-12}}</ref> [[Centered square number|centered square number]],<ref name="Centered square numbers">{{Cite OEIS|A001844|Centered square numbers|access-date=2016-06-12|}}</ref> Mertens function zero
:'''1014''' = 2<sup>10</sup>-10,<ref>{{cite OEIS|A000325|2^n - n|access-date=2022-05-24}}</ref> Mertens function zero, sum of the nontriangular numbers between successive triangular numbers
:'''1015''' = square pyramidal number<ref name="Square pyramidal numbers">{{Cite OEIS|A000330|Square pyramidal numbers|access-date=2016-06-12}}</ref>
:'''1016''' = member of the [[Mian–Chowla sequence]],<ref name="Mian-Chowla">{{Cite OEIS|A005282|Mian-Chowla sequence|access-date=2016-06-12}}</ref> stella octangula number, number of surface points on a cube with edge-length 14<ref name="A005897" />
:'''1017''' = generalized triacontagonal number<ref>{{Cite OEIS|A316729 |name=Generalized 30-gonal (or triacontagonal) numbers: m*(14*m - 13) with m = 0, +1, -1, +2, -2, +3, -3|access-date=2023-10-10}}</ref>
:'''1018''' = Mertens function zero, 1018<sup>16</sup> + 1 is prime<ref>{{cite OEIS|A006313|Numbers n such that n^16 + 1 is prime|access-date=2022-05-24}}</ref>
:'''1019''' = Sophie Germain prime,<ref name="Sophie Germain" /> [[Safe prime|safe prime]],<ref name="Safe primes">{{Cite OEIS|A005385|Safe primes p: (p-1)/2 is also prime|access-date=2016-06-12|}}</ref> [[Chen prime]]
:'''1020''' = [[Polydivisible number|polydivisible number]]
:'''1021''' = [[Twin prime|twin prime]] with '''1019'''. It is also a [[Lucky prime#Lucky primes|Lucky prime]].
:'''1022''' = [[Friedman number]]
:'''[[1023 (number)|1023]]''' = sum of five consecutive primes (193 + 197 + 199 + 211 + 223);<ref>{{Cite OEIS|A034964 |Sums of five consecutive primes.|access-date=2022-11-01}}</ref> the number of [[Three-dimensional space|three-dimensional]] [[Polycube|polycube]]s with 7 cells;<ref>{{Cite OEIS|A000162|Number of 3-dimensional polyominoes (or polycubes) with n cells.|access-date=2022-11-01}}</ref> number of [[Simplex#Elements|elements]] in a [[9-simplex|9-simplex]]; highest number one can count to on one's fingers using binary; magic number used in [[Engineering:Global Positioning System|Global Positioning System]] signals.
:'''[[1024 (number)|1024]]''' = 32<sup>2</sup> = 4<sup>5</sup> = 2<sup>10</sup>, the number of [[Byte|byte]]s in a [[Kilobyte|kilobyte]] (in 1999, the [[Organization:International Electrotechnical Commission|IEC]] coined [[Kibibyte|kibibyte]] to use for 1024 with kilobyte being 1000, but this convention has not been widely adopted). 1024 is the smallest 4-digit square and also a [[Friedman number]].
:'''1025''' = [[Proth number]] 2<sup>10</sup> + 1; member of [[Moser–de Bruijn sequence]], because its base-4 representation (100001<sub>4</sub>) contains only digits 0 and 1, or it's a sum of distinct powers of 4 (4<sup>5</sup> + 4<sup>0</sup>); Jacobsthal-Lucas number; hypotenuse of [[Primitive Pythagorean triangle|primitive Pythagorean triangle]]
:'''1026''' = sum of two distinct powers of 2 ([[1024 (number)|1024]] + [[2|2]])
:'''1027''' = sum of the squares of the first eight primes; can be written from base 2 to base 18 using only the digits 0 to 9.
:'''1028''' = sum of totient function for first 58 integers; can be written from base 2 to base 18 using only the digits 0 to 9; number of primes <= 2<sup>13</sup>.<ref name="auto3">{{cite OEIS|A007053|Number of primes < 2^n+1|access-date=2022-06-02}}</ref>
:'''1029''' = can be written from base 2 to base 18 using only the digits 0 to 9.
:'''1030''' = generalized heptagonal number
:'''1031''' = exponent and number of ones for the fifth base-10 [[Repunit|repunit prime]],<ref>{{Cite OEIS |A004023 |Indices of prime repunits: numbers n such that 11...111 (with n 1's)... is prime |access-date=2023-02-25}}</ref> Sophie Germain prime,<ref name="Sophie Germain" /> [[Super-prime|super-prime]], [[Chen prime]]
:'''1032''' = sum of two distinct powers of 2 ([[1024 (number)|1024]] + [[8|8]])
:'''1033''' = [[Emirp|emirp]], [[Twin prime|twin prime]] with '''1031'''
:'''1034''' = sum of 12 positive 9th powers<ref>{{Cite OEIS|A004801|Sum of 12 positive 9th powers|access-date=2023-10-10}}</ref>
:'''1035''' = [[Triangular number|triangular number]],<ref name="Triangular number">{{Cite OEIS|A000217|Triangular numbers|access-date=2016-06-12}}</ref> hexagonal number<ref name="Hexagonal number">{{Cite OEIS|A000384|Hexagonal numbers|access-date=2016-06-12|}}</ref>
:'''1036''' = central polygonal number<ref name="auto11">{{Cite OEIS|A000124|Central polygonal numbers (the Lazy Caterer's sequence): n(n+1)/2 + 1; or, maximal number of pieces formed when slicing a pancake with n cuts }}</ref>
:'''1037''' = number in E-toothpick sequence<ref>{{Cite OEIS|A161328|name=E-toothpick sequence (see Comments lines for definition)|access-date=2023-10-10}}</ref>
:'''1038''' = [[Parity (mathematics)|even]] [[Integer|integer]] that is an unordered sum of two [[Prime number|primes]] in exactly ''n'' ways<ref>{{Cite OEIS|A023036|Smallest positive even integer that is an unordered sum of two primes in exactly n ways|access-date=2023-10-10}}</ref>
:'''1039''' = [[Prime number|prime]] of the form 8n+7,<ref>{{Cite OEIS|A007522|Primes of the form 8n+7, that is, primes congruent to -1 mod 8|access-date=2023-10-10}}</ref> number of partitions of 30 that do not contain 1 as a part,<ref name="auto8">{{cite OEIS|A002865|Number of partitions of n that do not contain 1 as a part|access-date=2022-06-02}}</ref> [[Chen prime]]
:'''1040''' = 4<sup>5</sup> + 4<sup>2</sup>: sum of distinct powers of 4.<ref name="auto6">{{Cite OEIS|A000695|Moser-de Bruijn sequence: sums of distinct powers of 4|access-date=2023-10-10}}</ref> The number of pieces that could be seen in a 6 × 6 × 6× 6 Rubik's Tesseract.
:'''1041''' = sum of 11 positive 5th powers<ref>{{Cite web | url=https://oeis.org/A003356 | title=A003356 - Oeis }}</ref>
:'''1042''' = sum of 12 positive 5th powers<ref name="auto">{{Cite web | url=https://oeis.org/A003357 | title=A003357 - Oeis }}</ref>
:'''1043''' = number whose sum of [[Parity (mathematics)|even]] digits and sum of [[Parity (mathematics)|odd]] digits are even<ref>{{Cite web | url=https://oeis.org/A036301 | title=A036301 - Oeis }}</ref>
:'''1044''' = sum of distinct powers of 4<ref name="auto6"/>
:'''1045''' = octagonal number<ref>{{Cite web | url=https://oeis.org/A000567 | title=A000567 - Oeis }}</ref>
:'''1046''' = coefficient of f(q) (3rd order mock theta function)<ref>{{Cite web | url=https://oeis.org/A000025 | title=A000025 - Oeis }}</ref>
:'''1047''' = number of ways to split a strict composition of ''n'' into contiguous subsequences that have the same sum<ref>{{Cite web | url=https://oeis.org/A336130 | title=A336130 - Oeis }}</ref>
:'''1048''' = number of partitions of ''n'' into squarefree parts<ref>{{Cite web | url=https://oeis.org/A073576 | title=A073576 - Oeis }}</ref>
:'''1049''' = Sophie Germain prime,<ref name="Sophie Germain" /> [[Highly cototient number|highly cototient number]],<ref name="highly cototient">{{Cite web|url=https://oeis.org/A100827|title=Sloane's A100827 : Highly cototient numbers|website=The On-Line Encyclopedia of Integer Sequences | publisher=OEIS Foundation | access-date=June 12, 2016|archive-url=https://web.archive.org/web/20160610065744/https://oeis.org/A100827|archive-date=June 10, 2016|url-status=live}}</ref> [[Chen prime]]
:'''1050''' = 1050<sub>8</sub> to [[Decimal|decimal]] becomes a [[Pronic number|pronic number]] (552<sub>10</sub>),<ref>{{cite web | url=https://www.rapidtables.com/convert/number/base-converter.html?x=1050&sel1=3&sel2=10 | title=Base converter {{pipe}} number conversion }}</ref> number of parts in all partitions of 29 into distinct parts<ref name="auto46">{{cite OEIS|A015723|Number of parts in all partitions of n into distinct parts}}</ref>
:'''1051''' = centered pentagonal number,<ref name="Centered pentagonal">{{Cite web|url=https://oeis.org/A005891|title=Sloane's A005891 : Centered pentagonal numbers|website=The On-Line Encyclopedia of Integer Sequences | publisher=OEIS Foundation | access-date=June 12, 2016|archive-url=https://web.archive.org/web/20160610054330/https://oeis.org/A005891|archive-date=June 10, 2016|url-status=live}}</ref> centered decagonal number
:'''1052''' = number that is the sum of 9 positive 6th powers<ref>{{Cite web | url=https://oeis.org/A003365 | title=A003365 - Oeis }}</ref>
:'''1053''' = triangular matchstick number<ref name="auto5" />
:'''1054''' = centered triangular number<ref>{{Cite web | url=https://oeis.org/A005448 | title=A005448 - Oeis }}</ref>
:'''1055''' = number that is the sum of 12 positive 6th powers<ref>{{Cite web | url=https://oeis.org/A003368 | title=A003368 - Oeis }}</ref>
:'''1056''' = [[Pronic number|pronic number]]<ref name="pronic number">{{Cite web|url=https://oeis.org/A002378|title=Sloane's A002378 : Oblong (or promic, pronic, or heteromecic) numbers|website=The On-Line Encyclopedia of Integer Sequences | publisher=OEIS Foundation | access-date=June 12, 2016|archive-url=https://web.archive.org/web/20160609230431/https://oeis.org/A002378|archive-date=June 9, 2016|url-status=live}}</ref>
:'''1057''' = central polygonal number<ref>{{Cite web | url=https://oeis.org/A002061 | title=A002061 - Oeis }}</ref>
:'''1058''' = number that is the sum of 4 positive 5th powers,<ref>{{Cite web | url=https://oeis.org/A003349 | title=A003349 - Oeis }}</ref> area of a square with diagonal 46<ref name="area of a square with diagonal 2n">{{cite OEIS|A001105|2*n^2}}</ref>
:'''1059''' = number ''n'' such that n<sup>4</sup> is written in the form of a sum of four positive 4th powers<ref>{{Cite web | url=https://oeis.org/A003294 | title=A003294 - Oeis }}</ref>
:'''1060''' = sum of the first 25 primes
:'''1061''' = [[Emirp|emirp]], [[Twin prime|twin prime]] with '''1063''', number of prime numbers having four digits<ref>{{Cite OEIS|A006879|Number of primes with n digits.}}</ref>
:'''1062''' = number that is not the sum of two palindromes<ref name="auto10">{{Cite web | url=https://oeis.org/A035137 | title=A035137 - Oeis }}</ref>
:'''1063''' = [[Super-prime|super-prime]], sum of seven consecutive primes (137 + 139 + 149 + 151 + 157 + 163 + 167); near-wall-sun-sun prime<ref>{{Cite web|title=A347565: Primes p such that A241014(A000720(p)) is +1 or -1|url=https://oeis.org/A347565|website=The On-Line Encyclopedia of Integer Sequences | publisher=OEIS Foundation | access-date=January 19, 2022|archive-url=https://archive.today/20220325182252/https://oeis.org/A347565|archive-date=March 25, 2022|url-status=live}}</ref>
:'''1064''' = sum of two positive cubes<ref>{{Cite web | url=https://oeis.org/A003325 | title=A003325 - Oeis }}</ref>
:'''1065''' = generalized duodecagonal<ref>{{Cite web | url=https://oeis.org/A195162 | title=A195162 - Oeis }}</ref>
:'''1066''' = number whose sum of their divisors is a [[Square number|square]]<ref>{{Cite web | url=https://oeis.org/A006532 | title=A006532 - Oeis }}</ref>
:'''1067''' = number of strict [[Integer|integer]] [[Fraction|partitions]] of ''n'' in which are empty or have smallest [[Fraction|part]] not dividing the other ones<ref>{{Cite web | url=https://oeis.org/A341450 | title=A341450 - Oeis }}</ref>
:'''1068''' = number that is the sum of 7 positive 5th powers,<ref name="auto9"/> total number of parts in all partitions of 15<ref name="auto16">{{cite OEIS|A006128|Total number of parts in all partitions of n. Also, sum of largest parts of all partitions of n}}</ref>
:'''1069''' = [[Emirp|emirp]]<ref name="auto4">{{Cite web | url=https://oeis.org/A006567 | title=A006567 - Oeis }}</ref>
:'''1070''' = number that is the sum of 9 positive 5th powers<ref name="auto2">{{Cite web | url=https://oeis.org/A003354 | title=A003354 - Oeis }}</ref>
:'''1071''' = heptagonal number<ref name="heptagonal number">{{Cite web|url=https://oeis.org/A000566|title=Sloane's A000566 : Heptagonal numbers|website=The On-Line Encyclopedia of Integer Sequences | publisher=OEIS Foundation | access-date=June 12, 2016|archive-url=https://web.archive.org/web/20160611124321/https://oeis.org/A000566|archive-date=June 11, 2016|url-status=live}}</ref>
:'''1072''' = centered heptagonal number<ref name="centered heptagonal number">{{Cite web|url=https://oeis.org/A069099|title=Sloane's A069099 : Centered heptagonal numbers|website=The On-Line Encyclopedia of Integer Sequences | publisher=OEIS Foundation | access-date=June 12, 2016|archive-url=https://web.archive.org/web/20160609232609/https://oeis.org/A069099|archive-date=June 9, 2016|url-status=live}}</ref>
:'''1073''' = number that is the sum of 12 positive 5th powers<ref name="auto" />
:'''1074''' = number that is not the sum of two palindromes<ref name="auto10" />
:'''1075''' = number non-sum of two palindromes<ref name="auto10" />
:'''1076''' = number of strict trees weight ''n''<ref>{{Cite web | url=https://oeis.org/A273873 | title=A273873 - Oeis }}</ref>
:'''1077''' = number where [[7|7]] outnumbers every other digit in the number<ref>{{Cite web | url=https://oeis.org/A292457 | title=A292457 - Oeis }}</ref>
:'''1078''' = [[Euler number|Euler]] transform of negative integers<ref>{{Cite web | url=https://oeis.org/A073592 | title=A073592 - Oeis }}</ref>
:'''1079''' = every positive integer is the sum of at most 1079 tenth powers.
:'''1080''' = pentagonal number<ref name="Pentagonal number">{{Cite web|url=https://oeis.org/A000326|title=Sloane's A000326 : Pentagonal numbers|website=The On-Line Encyclopedia of Integer Sequences | publisher=OEIS Foundation | access-date=June 12, 2016|archive-url=https://web.archive.org/web/20160610054213/https://oeis.org/A000326|archive-date=June 10, 2016|url-status=live}}</ref>
:'''1081''' = triangular number,<ref name="Triangular number" /> member of [[Padovan sequence]]<ref name="Padovan sequence">{{Cite web|url=https://oeis.org/A000931|title=Sloane's A000931 : Padovan sequence|website=The On-Line Encyclopedia of Integer Sequences | publisher=OEIS Foundation | access-date=June 12, 2016|archive-url=https://web.archive.org/web/20160610051349/https://oeis.org/A000931|archive-date=June 10, 2016|url-status=live}}</ref>
:'''1082''' = central polygonal number<ref name="auto11" />
:'''1083''' = three-quarter [[Square number|square]],<ref>{{Cite web | url=https://oeis.org/A077043 | title=A077043 - Oeis }}</ref> number of partitions of 53 into prime parts
:'''1084''' = [[3|third]] spoke of a hexagonal spiral,<ref>{{Cite web | url=https://oeis.org/A056107 | title=A056107 - Oeis }}</ref> 1084<sup>64</sup> + 1 is prime
:'''1085''' = number of partitions of ''n'' into distinct [[Fraction|parts]] > or = [[2|2]]<ref>{{Cite web | url=https://oeis.org/A025147 | title=A025147 - Oeis }}</ref>
:'''1086''' = [[Smith number]],<ref>{{Cite web|url=https://oeis.org/A006753|title=Sloane's A006753 : Smith numbers|website=The On-Line Encyclopedia of Integer Sequences | publisher=OEIS Foundation | access-date=June 12, 2016|archive-url=https://web.archive.org/web/20160609223213/https://oeis.org/A006753|archive-date=June 9, 2016|url-status=live}}</ref> sum of totient function for first 59 integers
:'''1087''' = super-prime, [[Cousin prime|cousin prime]], [[Lucky prime|lucky prime]]<ref>{{Cite web|url=https://oeis.org/A031157|title=Sloane's A031157 : Numbers that are both lucky and prime|website=The On-Line Encyclopedia of Integer Sequences | publisher=OEIS Foundation | access-date=June 12, 2016|archive-url=https://web.archive.org/web/20160304202842/https://oeis.org/A031157|archive-date=March 4, 2016|url-status=live}}</ref>
:'''1088''' = octo-[[Triangular number|triangular number]], ([[Triangular number|triangular number]] result being [[136 (number)|136]])<ref>{{Cite web | url=https://oeis.org/A033996 | title=A033996 - Oeis }}</ref> sum of two distinct powers of 2, ([[1024 (number)|1024]] + [[64 (number)|64]])<ref>{{Cite web | url=https://oeis.org/A018900 | title=A018900 - Oeis }}</ref> number that is divisible by exactly seven primes with the inclusion of [[Multiplication|multiplicity]]<ref>{{Cite web | url=https://oeis.org/A046308 | title=A046308 - Oeis }}</ref>
:'''[[1089 (number)|1089]]''' = 33<sup>2</sup>, nonagonal number, centered octagonal number, first natural number whose digits in its decimal representation get reversed when multiplied by 9.<ref>{{Cite web|url=https://oeis.org/A001232|title=Sloane's A001232 : Numbers n such that 9*n = (n written backwards)|website=The On-Line Encyclopedia of Integer Sequences | publisher=OEIS Foundation | access-date=June 14, 2016|archive-url=https://web.archive.org/web/20151017134913/https://oeis.org/A001232|archive-date=October 17, 2015|url-status=live}}</ref>
:'''1090''' = sum of 5 positive 5th powers<ref>{{Cite web | url=https://oeis.org/A003350 | title=A003350 - Oeis }}</ref>
:'''1091''' = [[Cousin prime|cousin prime]] and [[Twin prime|twin prime]] with '''1093'''
:'''1092''' = divisible by the number of primes below it
:'''[[1093 (number)|1093]]''' = the smallest [[Wieferich prime]] (the only other known [[Wieferich prime]] is 3511<ref>Wells, D. ''The Penguin Dictionary of Curious and Interesting Numbers'' London: Penguin Group. (1987): 163</ref>), [[Twin prime|twin prime]] with '''1091''' and star number<ref name="Centered 12-gonal numbers">{{Cite web|url=https://oeis.org/A003154|title=Sloane's A003154 : Centered 12-gonal numbers. Also star numbers|website=The On-Line Encyclopedia of Integer Sequences | publisher=OEIS Foundation | access-date=June 12, 2016|archive-url=https://web.archive.org/web/20160611103753/https://oeis.org/A003154|archive-date=June 11, 2016|url-status=live}}</ref>
:'''1094''' = sum of 9 positive 5th powers,<ref name="auto2" /> 1094<sup>64</sup> + 1 is prime
:'''1095''' = sum of 10 positive 5th powers,<ref>{{Cite web | url=https://oeis.org/A003355 | title=A003355 - Oeis }}</ref> number that is not the sum of two palindromes
:'''1096''' = hendecagonal number,<ref>{{Cite web | url=https://oeis.org/A051682 | title=A051682 - Oeis }}</ref> number of strict solid partitions of 18<ref name="auto43">{{cite OEIS|A323657|Number of strict solid partitions of n}}</ref>
:'''1097''' = [[Emirp|emirp]],<ref name="auto4" /> [[Chen prime]]
:'''1098''' = multiple of 9 containing digit 9 in its [[Decimal|base-10]] representation<ref>{{Cite web | url=https://oeis.org/A121029 | title=A121029 - Oeis }}</ref>
:'''1099''' = number where 9 outnumbers every other digit<ref>{{Cite web | url=https://oeis.org/A292449 | title=A292449 - Oeis }}</ref>

=== 1100 to 1199 ===

:'''1100''' = number of partitions of 61 into distinct squarefree parts<ref>{{cite OEIS|A087188|number of partitions of n into distinct squarefree parts}}</ref>
:'''1101''' = pinwheel number<ref name="Pinwheel">{{cite OEIS|A059993|Pinwheel numbers: 2*n^2 + 6*n + 1}}</ref>
:'''1102''' = sum of totient function for first 60 integers
:'''1103''' = Sophie Germain prime,<ref name="Sophie Germain" /> [[Balanced prime|balanced prime]]<ref name="Balanced prime">{{Cite web|url=https://oeis.org/A006562|title=Sloane's A006562 : Balanced primes|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
:'''1104''' = [[Keith number]]<ref name="Keith number">{{Cite web|url=https://oeis.org/A007629|title=Sloane's A007629 : Repfigit (REPetitive FIbonacci-like diGIT) numbers (or Keith numbers)|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
:'''[[1105 (number)|1105]]''' = 33<sup>2</sup> + 4<sup>2</sup> = 32<sup>2</sup> + 9<sup>2</sup> = 31<sup>2</sup> + 12<sup>2</sup> = 23<sup>2</sup> + 24<sup>2</sup>, [[Carmichael number]],<ref>{{Cite web|url=https://oeis.org/A002997|title=Sloane's A002997 : Carmichael numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> [[Magic constant|magic constant]] of ''n'' × ''n'' normal [[Magic square|magic square]] and [[Eight queens puzzle|''n''-queens problem]] for ''n'' = 13, decagonal number,<ref name="Decagonal">{{Cite web|url=https://oeis.org/A001107|title=Sloane's A001107 : 10-gonal (or decagonal) numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> centered square number,<ref name="Centered square numbers" /> [[Fermat pseudoprime]]<ref name="auto93">{{cite OEIS|A001567|Fermat pseudoprimes to base 2, also called Sarrus numbers or Poulet numbers}}</ref>
:'''1106''' = number of regions into which the plane is divided when drawing 24 ellipses<ref name="auto91">{{cite OEIS|A051890|2*(n^2 - n + 1)}}</ref>
:'''1107''' = number of non-isomorphic strict T<sub>0</sub> multiset partitions of weight 8<ref>{{cite OEIS|A319560|Number of non-isomorphic strict T_0 multiset partitions of weight n}}</ref>
:'''1108''' = number k such that k<sup>64</sup> + 1 is prime
:'''1109''' = Friedlander-Iwaniec prime,<ref name="auto12">{{cite OEIS|A028916|Friedlander-Iwaniec primes: Primes of form a^2 + b^4}}</ref> [[Chen prime]]
:'''1110''' = k such that 2<sup>k</sup> + 3 is prime<ref>{{cite OEIS|A057732|Numbers k such that 2^k + 3 is prime}}</ref>
:'''1111''' = 11 × 101, palindrome that is a product of two palindromic primes<ref name="auto29">{{cite OEIS|A046376|Palindromes with exactly 2 palindromic prime factors (counted with multiplicity), and no other prime factors}}</ref>
:'''1112''' = k such that 9<sup>k</sup> - 2 is a prime<ref>{{cite OEIS|A128455|Numbers k such that 9^k - 2 is a prime}}</ref>
:'''1113''' = number of strict partions of 40<ref name="auto20">{{cite OEIS|A000009|Expansion of Product_{m > 0} (1 + x^m); number of partitions of n into distinct parts; number of partitions of n into odd parts}}</ref>
:'''1114''' = number of ways to write 22 as an orderless product of orderless sums<ref name="auto79">{{cite OEIS|A318949|Number of ways to write n as an orderless product of orderless sums}}</ref>
:'''1115''' = number of partitions of 27 into a prime number of parts<ref name="auto70">{{cite OEIS|A038499|Number of partitions of n into a prime number of parts}}</ref>
:'''1116''' = divisible by the number of primes below it
:'''1117''' = number of diagonally symmetric polyominoes with 16 cells,<ref name="auto23">{{cite OEIS|A006748|Number of diagonally symmetric polyominoes with n cells}}</ref> [[Chen prime]]
:'''1118''' = number of unimodular 2 × 2 matrices having all terms in {0,1,...,21}<ref name="auto54">{{cite OEIS|A210000|Number of unimodular 2 X 2 matrices having all terms in {0,1,...,n}}}</ref>
:'''1119''' = number of bipartite graphs with 9 nodes<ref>{{cite OEIS|A033995|Number of bipartite graphs with n nodes}}</ref>
:'''1120''' = number k such that k<sup>64</sup> + 1 is prime
:'''1121''' = number of squares between 34<sup>2</sup> and 34<sup>4</sup>.<ref name="auto40">{{cite OEIS|A028387|n + (n+1)^2}}</ref>
:'''1122''' = pronic number,<ref name="pronic number" /> divisible by the number of primes below it
:'''1123''' = [[Balanced prime|balanced prime]]<ref name="Balanced prime" />
:'''1124''' = [[Leyland number]]<ref name="Leyland number">{{Cite web|url=https://oeis.org/A076980|title=Sloane's A076980 : Leyland numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> = 2<sup>10</sup> + 10<sup>2</sup>
:'''1125''' = [[Achilles number]]
:'''1126''' = number of 2 × 2 non-singular integer matrices with entries from {0, 1, 2, 3, 4, 5}<ref>{{cite OEIS|A062801|Number of 2 X 2 non-singular integer matrices with entries from {0,...,n}}}</ref>
:'''1127''' = maximal number of pieces that can be obtained by cutting an annulus with 46 cuts<ref name="auto73">{{cite OEIS|A000096|n*(n+3)/2}}</ref>
:'''1128''' = triangular number,<ref name="Triangular number" /> hexagonal number,<ref name="Hexagonal number" /> divisible by the number of primes below it
:'''1129''' = number of lattice points inside a circle of radius 19<ref name="auto22">{{cite OEIS|A000328}}</ref>
:'''1130''' = skiponacci number<ref name="auto25">{{cite OEIS|A001608|Perrin sequence}}</ref>
:'''1131''' = number of edges in the [[:File:Hexagonal triangle.png|hexagonal triangle]] T(26)<ref name="auto60">{{cite OEIS|A140091|3*n*(n + 3)/2}}</ref>
:'''1132''' = number of simple unlabeled graphs with 9 nodes of 2 colors whose components are complete graphs<ref>{{cite OEIS|A005380}}</ref>
:'''1133''' = number of primitive subsequences of {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}<ref>{{cite OEIS|A051026|Number of primitive subsequences of 1, 2, ..., n}}</ref>
:'''1134''' = divisible by the number of primes below it, triangular matchstick number<ref name="auto5">{{cite OEIS|A045943|Triangular matchstick numbers: 3*n*(n+1)/2|access-date=2022-06-02}}</ref>
:'''1135''' = centered triangular number<ref name="auto52">{{cite OEIS|A005448|Centered triangular numbers: 3n(n-1)/2 + 1}}</ref>
:'''1136''' = number of [https://mathworld.wolfram.com/IndependentVertexSet.html independent vertex sets] and [https://mathworld.wolfram.com/VertexCover.html vertex covers] in the 7-[https://mathworld.wolfram.com/SunletGraph.html sunlet graph]<ref>{{cite OEIS|A080040|2*a(n-1) + 2*a(n-2) for n > 1}}</ref>
:'''1137''' = sum of values of vertices at level 5 of the hyperbolic Pascal pyramid<ref>{{cite OEIS|A264237|Sum of values of vertices at level n of the hyperbolic Pascal pyramid}}</ref>
:'''1138''' = recurring number in the works of George Lucas and his companies, beginning with his first feature film – ''THX 1138''; particularly, a special code for Easter eggs on ''Star Wars'' DVDs.
:'''1139''' = [[Wiener index|wiener index]] of the [[Windmill graph|windmill graph]] D(3,17)<ref name="auto90">{{cite OEIS|A033991|n*(4*n-1)}}</ref>
:'''1140''' = tetrahedral number<ref name="Tetrahedral nu">{{Cite web|url=https://oeis.org/A000292|title=Sloane's A000292 : Tetrahedral numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
:'''1141''' = 7-Knödel number<ref name="auto21">{{cite OEIS|A208155|7-Knödel numbers}}</ref>
:'''1142''' = n such that n<sup>32</sup> + 1 is prime<ref name="auto51">{{cite OEIS|A006315|Numbers n such that n^32 + 1 is prime}}</ref>
:'''1143''' = number of set partitions of 8 elements with 2 connectors<ref>{{cite OEIS|A185982|Triangle read by rows: number of set partitions of n elements with k connectors}}</ref>
:'''1144''' is not the sum of a pair of twin primes<ref name="auto99">{{cite OEIS|A007534|Even numbers that are not the sum of a pair of twin primes}}</ref>
:'''1145''' = 5-[[Knödel number]]<ref name="auto14">{{cite OEIS|A050993|5-Knödel numbers}}</ref>
:'''1146''' is not the sum of a pair of twin primes<ref name="auto99"/>
:'''1147''' = 31 × 37 (a product of 2 successive primes)<ref>{{cite OEIS|A006094|Products of 2 successive primes}}</ref>
:'''1148''' is not the sum of a pair of twin primes<ref name="auto99"/>
:'''1149''' = a product of two palindromic primes<ref>{{cite OEIS|A046368|Products of two palindromic primes}}</ref>
:'''1150''' = number of 11-iamonds without bilateral symmetry.<ref>{{Cite web|url=https://number.academy/1150|title=1150 (number)|website=The encyclopedia of numbers}}</ref>
:'''1151''' = first prime following a [[Prime gap|prime gap]] of 22,<ref name="Prime gap">{{Cite web|url=https://oeis.org/A000101|title=Sloane's A000101 : Increasing gaps between primes (upper end)|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-07-10}}</ref> [[Chen prime]]
:'''1152''' = [[Highly totient number|highly totient number]],<ref name="highly totient">{{Cite web|url=https://oeis.org/A097942|title=Sloane's A097942 : Highly totient numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> 3-smooth number (2<sup>7</sup>×3<sup>2</sup>), area of a square with diagonal 48,<ref name="area of a square with diagonal 2n"/> [[Achilles number]]
:'''1153''' = [[Super-prime|super-prime]], [[Proth prime]]<ref name="Proth prime">{{Cite web|url=https://oeis.org/A080076|title=Sloane's A080076 : Proth primes|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
:'''1154''' = 2 × 24<sup>2</sup> + 2 = number of points on surface of tetrahedron with edgelength 24<ref name="auto59">{{cite OEIS|
A005893|Number of points on surface of tetrahedron; coordination sequence for sodalite net (equals 2*n^2+2 for n > 0)}}</ref>
:'''1155''' = number of edges in the join of two cycle graphs, both of order 33<ref name="auto89">{{cite OEIS|n*(n+2)}}</ref>
:'''1156''' = 34<sup>2</sup>, octahedral number,<ref name="Octahedral number">{{Cite web|url=https://oeis.org/A005900|title=Sloane's A005900 : Octahedral numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> centered pentagonal number,<ref name="Centered pentagonal" /> centered hendecagonal number.<ref>{{Cite web|url=https://oeis.org/A069125|title=Sloane's A069125 : a(n) = (11*n^2 - 11*n + 2)/2|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
:'''1157''' = smallest number that can be written as n^2+1 without any prime factors that can be written as a^2+1.<ref>{{Cite web|url=https://number.academy/1157|title=1157 (number)|website=The encyclopedia of numbers}}</ref>
:'''1158''' = number of points on surface of octahedron with edgelength 17<ref name="auto61">{{cite OEIS|A005899|Number of points on surface of octahedron}}</ref>
:'''1159''' = member of the Mian–Chowla sequence,<ref name=Mian-Chowla /> a centered octahedral number<ref name="auto7">{{cite OEIS|A001845|Centered octahedral numbers (crystal ball sequence for cubic lattice)|access-date=2022-06-02}}</ref>
:'''1160''' = octagonal number<ref name="auto17">{{cite OEIS|A000567|Octagonal numbers: n*(3*n-2). Also called star numbers}}</ref>
:'''1161''' = sum of the first 26 primes
:'''1162''' = pentagonal number,<ref name="Pentagonal number" /> sum of totient function for first 61 integers
:'''1163''' = smallest prime > 34<sup>2</sup>.<ref name="auto57">{{cite OEIS|A007491|Smallest prime > n^2}}</ref> See [[Legendre's conjecture]]. [[Chen prime]].
:'''1164''' = number of chains of multisets that partition a normal multiset of weight 8, where a multiset is normal if it spans an initial interval of positive integers<ref>{{cite OEIS|A055887|Number of ordered partitions of partitions}}</ref>
:'''1165''' = 5-[[Knödel number]]<ref name="auto14"/>
:'''1166''' = heptagonal pyramidal number<ref name="auto82">{{cite OEIS|A002413|Heptagonal (or 7-gonal) pyramidal numbers}}</ref>
:'''1167''' = number of rational numbers which can be constructed from the set of integers between 1 and 43<ref name="auto56">{{cite OEIS|A018805}}</ref>
:'''1168''' = antisigma(49)<ref>{{cite OEIS|A024816|Antisigma(n): Sum of the numbers less than n that do not divide n}}</ref>
:'''1169''' = highly cototient number<ref name="highly cototient" />
:'''1170''' = highest possible score in a National Academic Quiz Tournaments (NAQT) match
:'''1171''' = super-prime
:'''1172''' = number of subsets of first 14 integers that have a sum divisible by 14<ref>{{Cite web|url=https://oeis.org/A063776|title=A063776 - OEIS|website=oeis.org}}</ref>
:'''1173''' = number of simple triangulation on a plane with 9 nodes<ref>{{Cite web|url=https://oeis.org/A000256|title=A000256 - OEIS|website=oeis.org}}</ref>
:'''1174''' = number of widely totally strongly normal compositions of 16
:'''1175''' = maximal number of pieces that can be obtained by cutting an annulus with 47 cuts<ref name="auto73"/>
:'''1176''' = triangular number<ref name="Triangular number" />
:'''1177''' = heptagonal number<ref name="heptagonal number" />
:'''1178''' = number of surface points on a cube with edge-length 15<ref name="A005897" />
:'''1179''' = number of different permanents of binary 7*7 matrices<ref>{{Cite web|url=https://number.academy/1179|title=1179 (number)|website=The encyclopedia of numbers}}</ref>
:'''1180''' = smallest number of non-integral partitions into non-integral power >1000.<ref>{{Cite web|url=https://oeis.org/A000339|title=A000339 - OEIS|website=oeis.org}}</ref>
:'''1181''' = smallest k over 1000 such that 8*10^k-49 is prime.<ref>{{Cite web|url=https://oeis.org/A271269|title=A271269 - OEIS|website=oeis.org}}</ref>
:'''1182''' = number of necklaces possible with 14 beads of 2 colors (that cannot be turned over)<ref>{{Cite web|url=https://oeis.org/A000031|title=A000031 - OEIS|website=oeis.org}}</ref>
:'''1183''' = pentagonal pyramidal number
:'''1184''' = amicable number with 1210<ref>{{cite book |title=Number Story: From Counting to Cryptography |url=https://archive.org/details/numberstoryfromc00higg_612 |url-access=limited |last=Higgins |first=Peter |year=2008 |publisher=Copernicus |location=New York |isbn=978-1-84800-000-1 |page=[https://archive.org/details/numberstoryfromc00higg_612/page/n69 61] }}</ref>
:'''1185''' = number of partitions of 45 into pairwise relatively prime parts<ref name="auto71">{{cite OEIS|A051424|Number of partitions of n into pairwise relatively prime parts}}</ref>
:'''1186''' = number of diagonally symmetric polyominoes with 15 cells,<ref name="auto23"/> number of partitions of 54 into prime parts
:'''1187''' = safe prime,<ref name="Safe primes" /> [[Stern prime]],<ref name="Stern prime">{{Cite web|url=https://oeis.org/A042978|title=Sloane's A042978 : Stern primes|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> balanced prime,<ref name="Balanced prime" /> [[Chen prime]]
:'''1188''' = first 4 digit multiple of 18 to contain 18<ref>{{Cite web|url=https://oeis.org/A121038|title=A121038 - OEIS|website=oeis.org}}</ref>
:'''1189''' = number of squares between 35<sup>2</sup> and 35<sup>4</sup>.<ref name="auto40"/>
:'''1190''' = pronic number,<ref name="pronic number" /> number of cards to build an 28-tier house of cards<ref name="auto45">{{cite OEIS|A005449|Second pentagonal numbers: n*(3*n + 1)/2}}</ref>
:'''1191''' = 35<sup>2</sup> - 35 + 1 = H<sub>35</sub> (the 35th Hogben number)<ref name="auto77">{{cite OEIS|A002061|Central polygonal numbers: n^2 - n + 1}}</ref>
:'''1192''' = sum of totient function for first 62 integers
:'''1193''' = a number such that 4<sup>1193</sup> - 3<sup>1193</sup> is prime, [[Chen prime]]
:'''1194''' =number of permutations that can be reached with 8 moves of 2 bishops and 1 rook on a 3 × 3 chessboard<ref>{{Cite web|url=https://oeis.org/A175654|title=A175654 - OEIS|website=oeis.org}}</ref>
:'''1195''' = smallest four digit number for which a<sup>−1</sup>(n) is an integer is a(n) is 2*a(n-1) - (-1)<sup>n</sup><ref>oeis.org/A062092</ref>
:'''1196''' = <math>\sum_{k=1}^{38} \sigma(k)</math><ref name="auto38">{{cite OEIS|A024916|Sum_1^n sigma(k)}}</ref>
:'''1197''' = pinwheel number<ref name="Pinwheel" />
:'''1198''' = centered heptagonal number<ref name="centered heptagonal number" />
:'''1199''' = area of the 20th [https://oeis.org/A080663/a080663.jpg conjoined trapezoid]<ref name="auto13">>{{cite OEIS|A080663|3*n^2 - 1}}</ref>

=== 1200 to 1299 ===

:'''1200''' = the '''[[Long thousand|long thousand]]''', ten "[[Long hundred|long hundred]]s" of 120 each, the traditional reckoning of large numbers in Germanic languages, the number of households the [[Finance:Nielsen ratings|Nielsen ratings]] sample,<ref>Meehan, Eileen R., ''Why TV is not our fault: television programming, viewers, and who's really in control'' Lanham, MD: Rowman & Littlefield, 2005</ref> number k such that k<sup>64</sup> + 1 is prime
:'''1201''' = centered square number,<ref name="Centered square numbers" /> [[Super-prime|super-prime]], centered decagonal number
:'''1202''' = [https://mathworld.wolfram.com/PlaneDivisionbyEllipses.html number of regions] the plane is divided into by 25 ellipses<ref name="auto91"/>
:'''1203''': first 4 digit number in the coordinating sequence for the (2,6,∞) tiling of the hyperbolic plane<ref>{{Cite web|url=https://oeis.org/A265070|title=A265070 - OEIS|website=oeis.org}}</ref>
:'''1204''': magic constant of a 7 × 7 × 7 magic cube<ref>{{Cite web|url=https://number.academy/1204|title=1204 (number)|website=The encyclopedia of numbers}}</ref>
:'''1205''' = number of partitions of 28 such that the number of odd parts is a part<ref name="auto72">{{cite OEIS|A240574|Number of partitions of n such that the number of odd parts is a part}}</ref>
:'''1206''' = 29-gonal number <ref>{{Cite web|url=https://oeis.org/A303815|title=A303815 - OEIS|website=oeis.org}}</ref>
:'''1207''' = composite de Polignac number<ref name="auto53">{{cite OEIS|A098237|Composite de Polignac numbers}}</ref>
:'''1208''' = number of strict chains of divisors starting with the superprimorial A006939(3)<ref>{{cite OEIS|A337070|Number of strict chains of divisors starting with the superprimorial A006939(n)}}</ref>
:'''1209''' = The product of all ordered non-empty subsets of {3,1} if {a,b} is a||b: 1209=1*3*13*31
:'''1210''' = amicable number with 1184<ref>Higgins, ibid.</ref>
:'''1211''' = composite de Polignac number<ref name="auto53"/>
:'''1212''' = <math>\sum_{k=0}^{17} p(k)</math>, where <math>p</math> is the number of partions of <math>k</math><ref>{{cite OEIS|A000070|Sum_{0..n} A000041(k)}}</ref>
:'''1213''' = [[Emirp|emirp]]
:'''1214''' = sum of first 39 composite numbers<ref name="auto94">{{cite OEIS|A053767|Sum of first n composite numbers}}</ref>
:'''1215''' = number of edges in the [[:File:Hexagonal triangle.png|hexagonal triangle]] T(27)<ref name="auto60"/>
:'''1216''' = nonagonal number<ref name="Nonagonal number">{{Cite web|url=https://oeis.org/A001106|title=Sloane's A001106 : 9-gonal (or enneagonal or nonagonal) numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
:'''1217''' = [[Super-prime|super-prime]], Proth prime<ref name="Proth prime" />
:'''1218''' = triangular matchstick number<ref name="auto5"/>
:'''1219''' = [[Mertens function]] zero, centered triangular number<ref name="auto52"/>
:'''1220''' = Mertens function zero, number of binary vectors of length 16 containing no singletons<ref name="auto50">{{cite OEIS|A006355|Number of binary vectors of length n containing no singletons}}</ref>
:'''1221''' = product of the first two digit, and three digit repdigit
:'''1222''' = hexagonal pyramidal number
:'''1223''' = Sophie Germain prime,<ref name="Sophie Germain" /> balanced prime, 200th prime number<ref name="Balanced prime" />
:'''1224''' = number of edges in the join of two cycle graphs, both of order 34<ref name="auto89"/>
:'''1225''' = 35<sup>2</sup>, [[Square triangular number|square triangular number]],<ref>{{Cite web|url=https://oeis.org/A001110|title=Sloane's A001110 : Square triangular numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> hexagonal number,<ref name="Hexagonal number" /> centered octagonal number,<ref name="Centered octagonal number">{{Cite web|url=https://oeis.org/A016754|title=Sloane's A016754 : Odd squares: a(n) = (2n+1)^2. Also centered octagonal numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> icosienneagonal,<ref>{{cite OEIS|A303815|Generalized 29-gonal (or icosienneagonal) numbers}}</ref> hexacontagonal<ref>{{cite OEIS|A249911|60-gonal (hexacontagonal) numbers}}</ref> and hecatonicositetragonal (124-gonal).
:'''1226''' = number of rooted identity trees with 15 nodes <ref>{{Cite web|url=https://oeis.org/A004111|title=A004111 - OEIS|website=oeis.org}}</ref>
:'''1227''' = smallest number representable as the sum of 3 triangular numbers in 27 ways<ref>{{Cite web|url=https://oeis.org/A061262|title=A061262 - OEIS|website=oeis.org}}</ref>
:'''1228''' = sum of totient function for first 63 integers
:'''1229''' = Sophie Germain prime,<ref name="Sophie Germain" /> number of primes between 0 and 10000, [[Emirp|emirp]]
:'''1230''' = the Mahonian number: T(9, 6)<ref name="A008302">{{cite OEIS|A008302|Triangle of Mahonian numbers T(n,k): coefficients in expansion of Product{0..n-1} (1 + x + ... + x^i), where k ranges from 0 to A000217(n-1). Also enumerates permutations by their major index}}</ref>
:'''1231''' = smallest mountain emirp, as 121, smallest mountain number is 11 × 11
:'''1232''' = number of labeled ordered set of partitions of a 7-set into odd parts<ref>{{Cite web|url=https://oeis.org/A006154|title=A006154 - OEIS|website=oeis.org}}</ref>
:'''1233''' = 12<sup>2</sup> + 33<sup>2</sup>
:'''1234''' = number of parts in all partitions of 30 into distinct parts,<ref name="auto46"/> smallest whole number containing all numbers from 1 to 4
:'''1235''' = excluding duplicates, contains the first four Fibbonacci numbers <ref>{{Cite web|url=https://oeis.org/A000045|title=A000045 - OEIS|website=oeis.org}}</ref>
:'''1236''' = 617 + 619: sum of twin prime pair<ref name="auto48">{{cite OEIS|A054735|Sums of twin prime pairs}}</ref>
:'''1237''' = prime of the form 2p-1
:'''1238''' = number of partitions of 31 that do not contain 1 as a part<ref name="auto8"/>
:'''1239''' = toothpick number in 3D<ref>{{Cite web|url=https://oeis.org/A160160|title=A160160 - OEIS|website=oeis.org}}</ref>
:'''1240''' = square pyramidal number<ref name="Square pyramidal numbers" />
:'''1241''' = centered cube number<ref>{{Cite web|url=https://oeis.org/A005898|title=Sloane's A005898 : Centered cube numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
:'''1242''' = decagonal number<ref name="Decagonal" />
:'''1243''' = composite de Polignac number<ref name="auto53"/>
:'''1244''' = number of complete partitions of 25<ref>{{cite OEIS|A126796|Number of complete partitions of n}}</ref>
:'''1245''' = Number of labeled spanning intersecting set-systems on 5 vertices.<ref>oeis.org/A305843</ref>
:'''1246''' = number of partitions of 38 such that no part occurs more than once<ref>{{Cite web|url=https://oeis.org/A007690|title=A007690 - OEIS|website=oeis.org}}</ref>
:'''1247''' = pentagonal number<ref name="Pentagonal number" />
:'''1248''' = the first four powers of 2 concatenated together
:'''1249''' = emirp, [[Trimorphic number|trimorphic number]]<ref>{{Cite web|url=https://oeis.org/A033819|title=Sloane's A033819 : Trimorphic numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
:'''1250''' = area of a square with diagonal 50<ref name="area of a square with diagonal 2n"/>
:'''1251''' = 2 × 25<sup>2</sup> + 1 = number of different 2 × 2 determinants with integer entries from 0 to 25<ref name="auto32">{{cite OEIS|A058331|2*n^2 + 1}}</ref>
:'''1252''' = 2 × 25<sup>2</sup> + 2 = number of points on surface of tetrahedron with edgelength 25<ref name="auto59"/>
:'''1253''' = number of partitions of 23 with at least one distinct part<ref name="auto66">{{cite OEIS|A144300|Number of partitions of n minus number of divisors of n}}</ref>
:'''1254''' = number of partitions of 23 into relatively prime parts<ref>{{cite OEIS|A000837|Number of partitions of n into relatively prime parts. Also aperiodic partitions.}}</ref>
:'''1255''' = Mertens function zero, number of ways to write 23 as an orderless product of orderless sums,<ref name="auto79"/> number of partitions of 23<ref name="auto35">{{cite OEIS|A000041|a(n) is the number of partitions of n (the partition numbers)}}</ref>
:'''1256''' = 1 × 2 × (5<sup>2</sup>)<sup>2</sup> + 6,<ref name="ReferenceA">{{cite OEIS|A193757|Numbers which can be written with their digits in order and using only a plus and a squaring operator}}</ref> Mertens function zero
:'''1257''' = number of lattice points inside a circle of radius 20<ref name="auto22"/>
:'''1258''' = 1 × 2 × (5<sup>2</sup>)<sup>2</sup> + 8,<ref name="ReferenceA"/> Mertens function zero
:'''1259''' = [[Highly cototient number|highly cototient number]]<ref name="highly cototient" />
:'''1260''' = [[Highly composite number|highly composite number]],<ref name="Highly composite">{{Cite web|url=https://oeis.org/A002182|title=Sloane's A002182 : Highly composite numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> pronic number,<ref name="pronic number" /> the smallest [[Vampire number|vampire number]],<ref name="Vampire number">{{Cite web|url=https://oeis.org/A014575|title=Sloane's A014575 : Vampire numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> sum of totient function for first 64 integers, number of strict partions of 41<ref name="auto20"/> and appears twice in the [[Religion:Book of Revelation|Book of Revelation]]
:'''1261''' = star number,<ref name="Centered 12-gonal numbers" /> Mertens function zero
:'''1262''' = maximal number of regions the plane is divided into by drawing 36 circles<ref name="auto27">{{cite OEIS|A014206|n^2 + n + 2}}</ref>
:'''1263''' = rounded total surface area of a regular tetrahedron with edge length 27<ref name="auto74">{{cite OEIS|A070169|Rounded total surface area of a regular tetrahedron with edge length n}}</ref>
:'''1264''' = sum of the first 27 primes
:'''1265''' = number of rooted trees with 43 vertices in which vertices at the same level have the same degree<ref name="auto28">{{cite OEIS|A003238|Number of rooted trees with n vertices in which vertices at the same level have the same degree}}</ref>
:'''1266''' = centered pentagonal number,<ref name="Centered pentagonal" /> Mertens function zero
:'''1267''' = 7-Knödel number<ref name="auto21"/>
:'''1268''' = number of partitions of 37 into prime power parts<ref name="auto87">{{cite OEIS|A023894|Number of partitions of n into prime power parts}}</ref>
:'''1269''' = least number of triangles of the [[Spiral of Theodorus]] to complete 11 revolutions<ref name="auto85">{{cite OEIS|A072895|Least k for the Theodorus spiral to complete n revolutions}}</ref>
:'''1270''' = 25 + 24×26 + 23×27,<ref>{{cite OEIS|A100040|2*n^2 + n - 5}}</ref> Mertens function zero
:'''1271''' = sum of first 40 composite numbers<ref name="auto94"/>
:'''1272''' = sum of first 41 nonprimes<ref name="ReferenceB">{{cite OEIS|A051349|Sum of first n nonprimes}}</ref>
:'''1273''' = 19 × 67 = 19 × prime(19)<ref name="cite OEIS|A033286|n * primen">{{cite OEIS|A033286|n * prime(n)}}</ref>
:'''1274''' = sum of the nontriangular numbers between successive triangular numbers
:'''1275''' = triangular number,<ref name="Triangular number" /> sum of the first 50 natural numbers
:'''1276''' = number of irredundant sets in the 25-cocktail party graph<ref name="auto34">{{cite OEIS|A084849|1 + n + 2*n^2}}</ref>
:'''1277''' = the start of a prime constellation of length 9 (a "prime nonuple")
:'''1278''' = number of Narayana's cows and calves after 20 years<ref name="auto98">{{cite OEIS|A000930|Narayana's cows sequence}}</ref>
:'''1279''' = Mertens function zero, [[Mersenne prime]] exponent
:'''1280''' = Mertens function zero, number of parts in all compositions of 9<ref>{{cite OEIS|A001792|(n+2)*2^(n-1)}}</ref>
:'''1281''' = octagonal number<ref name="auto17"/>
:'''1282''' = Mertens function zero, number of partitions of 46 into pairwise relatively prime parts<ref name="auto71"/>
:'''1283''' = safe prime<ref name="Safe primes" />
:'''1284''' = 641 + 643: sum of twin prime pair<ref name="auto48"/>
:'''1285''' = Mertens function zero, number of free nonominoes, number of parallelogram polyominoes with 10 cells.<ref>{{cite OEIS|A006958|Number of parallelogram polyominoes with n cells (also called staircase polyominoes, although that term is overused)}}</ref>
:'''1286''' = number of inequivalent connected planar figures that can be formed from five 1 X 2 rectangles (or dominoes) such that each pair of touching rectangles shares exactly one edge, of length 1, and the adjacency graph of the rectangles is a tree<ref>{{cite OEIS|A216492|Number of inequivalent connected planar figures that can be formed from n 1 X 2 rectangles (or dominoes) such that each pair of touching rectangles shares exactly one edge, of length 1, and the adjacency graph of the rectangles is a tree}}</ref>
:'''1287''' = <math>{13 \choose 5}</math><ref>{{cite OEIS|A007318|Pascal's triangle read by rows}}</ref>
:'''1288''' = heptagonal number<ref name="heptagonal number" />
:'''[[1289 (number)|1289]]''' = Sophie Germain prime,<ref name="Sophie Germain" /> Mertens function zero
:'''1290''' = <math>\frac{1289 + 1291}{2}</math>, average of a twin prime pair<ref>{{cite OEIS|A014574|Average of twin prime pairs}}</ref>
:'''1291''' = largest prime < 6<sup>4</sup>,<ref>{{cite OEIS|A173831|Largest prime < n^4}}</ref> Mertens function zero
:'''1292''' = number such that phi(1292) = phi(sigma(1292)),<ref>{{cite OEIS|A006872|Numbers k such that phi(k) equals phi(sigma(k))}}</ref> Mertens function zero
:'''1293''' = <math>\sum_{j=1}^n j \times prime(j)</math><ref>{{cite OEIS|A014285|Sum_{1..n} j*prime(j)}}</ref>
:'''1294''' = rounded volume of a regular octahedron with edge length 14<ref name="auto84">{{cite OEIS|A071400|Rounded volume of a regular octahedron with edge length n}}</ref>
:'''1295''' = number of edges in the join of two cycle graphs, both of order 35<ref name="auto89"/>
:'''1296''' = 36<sup>2</sup> = 6<sup>4</sup>, sum of the cubes of the first eight positive integers, the number of [[Rectangle|rectangle]]s on a normal 8 × 8 chessboard, also the maximum font size allowed in Adobe InDesign
:'''1297''' = [[Super-prime|super-prime]], Mertens function zero, pinwheel number<ref name="Pinwheel" />
:'''1298''' = number of partitions of 55 into prime parts
:'''1299''' = Mertens function zero, number of partitions of 52 such that the smallest part is greater than or equal to number of parts<ref name="auto75">{{cite OEIS|A003114|Number of partitions of n into parts 5k+1 or 5k+4}}</ref>

=== 1300 to 1399 ===

:'''1300''' = Sum of the first 4 fifth powers, mertens function zero, largest possible win margin in an NAQT match; smallest even odd-factor hyperperfect number
:'''1301''' = centered square number,<ref name="Centered square numbers" /> Honaker prime,<ref name="auto39">{{cite OEIS|A033548|Honaker primes: primes P(k) such that sum of digits of P(k) equals sum of digits of k}}</ref> number of trees with 13 unlabeled nodes<ref>{{cite OEIS|A000055|Number of trees with n unlabeled nodes}}</ref>
:'''1302''' = Mertens function zero, number of edges in the [[:File:Hexagonal triangle.png|hexagonal triangle]] T(28)<ref name="auto60"/>
:'''1303''' = prime of form 21n+1 and 31n+1<ref>{{Cite web|url=https://oeis.org/A124826|title=A124826 - OEIS|website=oeis.org}}</ref><ref>{{Cite web|url=https://oeis.org/A142005|title=A142005 - OEIS|website=oeis.org}}</ref>
:'''1304''' = sum of 1304<sub>6</sub> and 1304 <sub>9</sub> which is 328+976
:'''1305''' = triangular matchstick number<ref name="auto5"/>
:'''1306''' = Mertens function zero. In base 10, raising the digits of 1306 to powers of successive integers equals itself: {{nowrap|1=1306 = 1<sup>1</sup> + 3<sup>2</sup> + 0<sup>3</sup> + 6<sup>4</sup>.}} [[135 (number)|135]], [[175 (number)|175]], 518, and 598 also have this property. Centered triangular number.<ref name="auto52"/>
:'''1307''' = safe prime<ref name="Safe primes" />
:'''1308''' = sum of totient function for first 65 integers
:'''1309''' = the first [[Sphenic number|sphenic number]] followed by two consecutive such number
:'''1310''' = smallest number in the middle of a set of three sphenic numbers
:'''1311''' = number of integer partitions of 32 with no part dividing all the others<ref name="auto30">{{cite OEIS|A338470|Number of integer partitions of n with no part dividing all the others}}</ref>
:'''1312''' = member of the Mian-Chowla sequence;<ref name=Mian-Chowla />
:'''1313''' = sum of all parts of all partitions of 14 <ref>{{Cite web|url=https://oeis.org/A066186|title=A066186 - OEIS|website=oeis.org}}</ref>
:'''1314''' = number of integer partitions of 41 whose distinct parts are connected<ref name="auto86">{{cite OEIS|A304716|Number of integer partitions of n whose distinct parts are connected}}</ref>
:'''1315''' = 10^(2n+1)-7*10^n-1 is prime.<ref>{{Cite web|url=https://oeis.org/A115073|title=A115073 - OEIS|website=oeis.org}}</ref>
:'''1316''' = Euler transformation of sigma(11)<ref>{{Cite web|url=https://oeis.org/A061256|title=A061256 - OEIS|website=oeis.org}}</ref>
:'''1317''' = 1317 Only odd four digit number to divide the concatenation of all number up to itself in base 25<ref>{{Cite web|url=https://oeis.org/A061954|title=A061954 - OEIS|website=oeis.org}}</ref>
:'''1318'''<sup>512</sup> + 1 is prime,<ref>{{cite OEIS|A057465|Numbers k such that k^512 + 1 is prime}}</ref> Mertens function zero
:'''1319''' = safe prime<ref name="Safe primes" />
:'''1320''' = 659 + 661: sum of twin prime pair<ref name="auto48"/>
:'''1321''' = Friedlander-Iwaniec prime<ref name="auto12"/>
:'''1322''' = area of the 21st [https://oeis.org/A080663/a080663.jpg conjoined trapezoid]<ref name="auto13"/>
:'''1323''' = [[Achilles number]]
:'''1324''' = if D(n) is the nth representation of 1, 2 arranged lexicographically. 1324 is the first non-1 number which is D(D(x))<ref>{{Cite web|url=https://oeis.org/A030299|title=A030299 - OEIS|website=oeis.org}}</ref>
:'''1325''' = [[Markov number]],<ref name="Markov number">{{Cite web|url=https://oeis.org/A002559|title=Sloane's A002559 : Markoff (or Markov) numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> centered tetrahedral number<ref name="auto42">{{cite OEIS|A005894|Centered tetrahedral numbers}}</ref>
:'''1326''' = triangular number,<ref name="Triangular number" /> hexagonal number,<ref name="Hexagonal number" /> Mertens function zero
:'''1327''' = first prime followed by 33 consecutive composite numbers
:'''1328''' = sum of totient function for first 66 integers
:'''1329''' = Mertens function zero, sum of first 41 composite numbers<ref name="auto94"/>
:'''1330''' = tetrahedral number,<ref name="Leyland number" /> forms a [[Ruth–Aaron pair]] with 1331 under second definition
:'''1331''' = 11<sup>3</sup>, centered heptagonal number,<ref name="centered heptagonal number" /> forms a Ruth–Aaron pair with 1330 under second definition. This is the only non-trivial cube of the form ''x''<sup>2</sup> + ''x'' − 1, for ''x'' = 36.
:'''1332''' = pronic number<ref name="pronic number" />
:'''1333''' = 37<sup>2</sup> - 37 + 1 = H<sub>37</sub> (the 37th Hogben number)<ref name="auto77"/>
:'''1334''' = maximal number of regions the plane is divided into by drawing 37 circles<ref name="auto27"/>
:'''1335''' = pentagonal number,<ref name="Pentagonal number" /> Mertens function zero
:'''1336''' = sum of gcd(x, y) for 1 <= x, y <= 24,<ref>{{cite OEIS|A018806|Sum of gcd(x, y)}}</ref> Mertens function zero
:'''1337''' = Used in the novel form of spelling called [[Leet|leet]]. Approximate melting point of [[Chemistry:Gold|gold]] in [[Kelvin|kelvin]]s.
:'''1338''' = atomic number of the noble element of period 18,<ref>{{cite OEIS|A018227|Magic numbers: atoms with full shells containing any of these numbers of electrons are considered electronically stable}}</ref> Mertens function zero
:'''1339''' = First 4 digit number to appear twice in the sequence of sum of cubes of primes dividing n<ref>{{Cite web|url=https://oeis.org/A005064|title=A005064 - OEIS|website=oeis.org}}</ref>
:'''1340''' = k such that 5 × 2<sup>k</sup> - 1 is prime<ref name="auto69">{{cite OEIS|A001770|Numbers k such that 5*2^k - 1 is prime}}</ref>
:'''1341''' = First mountain number with 2 jumps of more than one.
:'''1342''' = <math>\sum_{k=1}^{40} \sigma(k)</math>,<ref name="auto38"/> Mertens function zero
:'''1343''' = [https://oeis.org/A144391/a144391.jpg cropped hexagone]<ref name="auto44">{{cite OEIS|A144391|3*n^2 + n - 1}}</ref>
:'''1344''' = 37<sup>2</sup> - 5<sup>2</sup>, the only way to express 1344 as a difference of prime squares<ref name="auto96">{{cite OEIS|A090781|Numbers that can be expressed as the difference of the squares of primes in just one distinct way}}</ref>
:'''1345''' = k such that k, k+1 and k+2 are products of two primes<ref name="auto81">{{cite OEIS|A056809|Numbers k such that k, k+1 and k+2 are products of two primes}}</ref>
:'''1346'''= number of locally disjointed rooted trees with 10 nodes<ref>{{Cite web|url=https://oeis.org/A316473|title=A316473 - OEIS|website=oeis.org}}</ref>
:'''1347''' = concatenation of first 4 [[Lucas number]]s <ref>{{Cite web|url=https://oeis.org/A000032|title=A000032 - OEIS|website=oeis.org}}</ref>
:'''1348''' = number of ways to stack 22 pennies such that every penny is in a stack of one or two<ref>{{Cite web|url=https://number.academy/1348|title=1348 (number)|website=The encyclopedia of numbers}}</ref>
:'''1349''' = Stern-Jacobsthal number<ref name="auto15">{{cite OEIS|A101624|Stern-Jacobsthal number}}</ref>
:'''1350''' = nonagonal number<ref name="Nonagonal number" />
:'''1351''' = number of partitions of 28 into a prime number of parts<ref name="auto70"/>
:'''1352''' = number of surface points on a cube with edge-length 16,<ref name="A005897" /> [[Achilles number]]
:'''1353''' = 2 × 26<sup>2</sup> + 1 = number of different 2 × 2 determinants with integer entries from 0 to 26<ref name="auto32"/>
:'''1354''' = 2 × 26<sup>2</sup> + 2 = number of points on surface of tetrahedron with edgelength 26<ref name="auto59"/>
:'''1355''' appears for the first time in the [[Recamán's sequence]] at n = 325,374,625,245.<ref>{{cite OEIS|A064228|From Recamán's sequence (A005132): values of n achieving records in A057167}}</ref> Or in other words A057167(1355) = 325,374,625,245<ref>{{cite OEIS|A057167|Term in Recamán's sequence A005132 where n appears for first time, or -1 if n never appears}}</ref><ref>{{cite OEIS|A064227|From Recamán's sequence (A005132): record values in A057167}}</ref>
:'''1356''' is not the sum of a pair of twin primes<ref name="auto99"/>
:'''1357''' = number of nonnegative solutions to x<sup>2</sup> + y<sup>2</sup> ≤ 41<sup>2</sup><ref name="auto65">{{cite OEIS|A000603}}</ref>
:'''1358''' = rounded total surface area of a regular tetrahedron with edge length 28<ref name="auto74"/>
:'''1359''' is the 42d term of Flavius Josephus's sieve<ref>{{cite OEIS|A000960|Flavius Josephus's sieve: Start with the natural numbers; at the k-th sieving step, remove every (k+1)-st term of the sequence remaining after the (k-1)-st sieving step; iterate}}</ref>
:'''1360''' = 37<sup>2</sup> - 3<sup>2</sup>, the only way to express 1360 as a difference of prime squares<ref name="auto96"/>
:'''1361''' = first prime following a [[Prime gap|prime gap]] of 34,<ref name="Prime gap" /> centered decagonal number, Honaker prime<ref name="auto39"/>
:'''1362''' = number of achiral integer partitions of 48<ref name="auto64">{{cite OEIS|A330224|Number of achiral integer partitions of n}}</ref>
:'''1363''' = the number of ways to modify a circular arrangement of 14 objects by swapping one or more adjacent pairs<ref>{{cite OEIS|A001610|a(n-1) + a(n-2) + 1}}</ref>
:'''1364''' = Lucas number<ref>{{cite OEIS|A000032|Lucas numbers: L(n-1) + L(n-2)}}</ref>
:'''1365''' = pentatope number<ref name="Pentatope number">{{Cite web|url=https://oeis.org/A000332|title=Sloane's A000332 : Binomial coefficient binomial(n,4) = n*(n-1)*(n-2)*(n-3)/24|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
:'''1366''' = Arima number, after Yoriyuki Arima who in 1769 constructed this sequence as the number of moves of the outer ring in the optimal solution for the Chinese Rings puzzle<ref>{{cite OEIS|A005578|Arima sequence}}</ref>
:'''1367''' = safe prime,<ref name="Safe primes" /> balanced prime, sum of three, nine, and eleven consecutive primes (449 + 457 + 461, 131 + 137 + 139 + 149 + 151 + 157 + 163 + 167 + 173, and 101 + 103 + 107 + 109 + 113 + 127 + 131 + 137 + 139 + 149 + 151),<ref name="Balanced prime" />
:'''1368''' = number of edges in the join of two cycle graphs, both of order 36<ref name="auto89"/>
:'''1369''' = 37<sup>2</sup>, centered octagonal number<ref name="Centered octagonal number" />
:'''1370''' = σ<sub>2</sub>(37): sum of squares of divisors of 37<ref name="auto76">{{cite OEIS|A001157|sigma_2(n): sum of squares of divisors of n}}</ref>
:'''1371''' = sum of the first 28 primes
:'''1372''' = [[Achilles number]]
:'''1373''' = number of lattice points inside a circle of radius 21<ref name="auto22"/>
:'''1374''' = number of unimodular 2 × 2 matrices having all terms in {0,1,...,23}<ref name="auto54"/>
:'''1375''' = decagonal pyramidal number<ref name="auto62">{{cite OEIS|A007585|10-gonal (or decagonal) pyramidal numbers}}</ref>
:'''1376''' = primitive abundant number ([[Abundant number|abundant number]] all of whose proper divisors are deficient numbers)<ref name="auto92">{{cite OEIS|A071395|Primitive abundant numbers (abundant numbers all of whose proper divisors are deficient numbers)}}</ref>
:'''1377''' = maximal number of pieces that can be obtained by cutting an annulus with 51 cuts<ref name="auto73"/>
:'''1378''' = triangular number<ref name="Triangular number" />
:'''1379''' = [[Magic constant|magic constant]] of ''n'' × ''n'' normal [[Magic square|magic square]] and [[Eight queens puzzle|''n''-queens problem]] for ''n'' = 14.
:'''1380''' = number of 8-step mappings with 4 inputs<ref name="auto95">{{cite OEIS|A005945|Number of n-step mappings with 4 inputs}}</ref>
:'''1381''' = centered pentagonal number<ref name="Centered pentagonal" /> Mertens function zero
:'''1382''' = first 4 digit tetrachi number <ref>{{Cite web|url=https://oeis.org/A001631|title=A001631 - OEIS|website=oeis.org|accessdate=25 June 2023}}</ref>
:'''1383''' = 3 × 461. 10<sup>1383</sup> + 7 is prime<ref>{{cite OEIS|A088274|Numbers k such that 10^k + 7 is prime}}</ref>
:'''1384''' = <math>\sum_{k=1}^{41} \sigma(k)</math><ref name="auto38"/>
:'''1385''' = up/down number<ref>{{cite OEIS|A000111|Euler or up/down numbers: e.g.f. sec(x) + tan(x)}}</ref>
:'''1386''' = octagonal pyramidal number<ref>{{cite OEIS|A002414|Octagonal pyramidal numbers}}</ref>
:'''1387''' = 5th [[Fermat pseudoprime]] of base 2,<ref>{{Cite web|url=https://oeis.org/A001567|title=Sloane's A001567 : Fermat pseudoprimes to base 2|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> 22nd [[Centered hexagonal number|centered hexagonal number]] and the 19th decagonal number,<ref name="Decagonal" /> second [[Super-Poulet number]].<ref>{{Cite web|url=https://oeis.org/A050217|title=Sloane's A050217 : Super-Poulet numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
:'''1388''' = 4 × 19<sup>2</sup> - 3 × 19 + 1 and is therefore on the x-axis of Ulams spiral<ref>{{cite OEIS|A054552|4*n^2 - 3*n + 1}}</ref>
:'''1389''' = sum of first 42 composite numbers<ref name="auto94"/>
:'''1390''' = sum of first 43 nonprimes<ref name="ReferenceB"/>
:'''1391''' = number of rational numbers which can be constructed from the set of integers between 1 and 47<ref name="auto56"/>
:'''1392''' = number of edges in the [[:File:Hexagonal triangle.png|hexagonal triangle]] T(29)<ref name="auto60"/>
:'''1393''' = 7-Knödel number<ref name="auto21"/>
:'''1394''' = sum of totient function for first 67 integers
:'''1395''' = [[Vampire number|vampire number]],<ref name="Vampire number" /> member of the Mian–Chowla sequence<ref name=Mian-Chowla /> triangular matchstick number<ref name="auto5"/>
:'''1396''' = centered triangular number<ref name="auto52"/>
:'''1397''' = <math>\left \lfloor 5^{\frac{9}{2}} \right \rfloor</math><ref>{{cite OEIS|A017919|Powers of sqrt(5) rounded down}}</ref>
:'''1398''' = number of integer partitions of 40 whose distinct parts are connected<ref name="auto86"/>
:'''1399''' = emirp<ref>{{cite OEIS|A109308|Lesser emirps (primes whose digit reversal is a larger prime)}}</ref>

=== 1400 to 1499 ===
:'''1400''' = number of sum-free subsets of {1, ..., 15}<ref name="auto41">{{cite OEIS|A007865|Number of sum-free subsets of {1, ..., n}}}</ref>
:'''1401''' = pinwheel number<ref name="Pinwheel" />
:'''1402''' = number of integer partitions of 48 whose augmented differences are distinct<ref name="auto19">{{cite OEIS|A325349|Number of integer partitions of n whose augmented differences are distinct}}</ref>
:'''1403''' = smallest x such that M(x) = 11, where M() is [[Mertens function]]<ref name="ReferenceC">{{cite OEIS|A051400|Smallest value of x such that M(x) equals n, where M() is Mertens's function A002321}}</ref>
:'''1404''' = heptagonal number<ref name="heptagonal number" />
:'''1405''' = 26<sup>2</sup> + 27<sup>2</sup>, 7<sup>2</sup> + 8<sup>2</sup> + ... + 16<sup>2</sup>, centered square number<ref name="Centered square numbers" />
:'''1406''' = pronic number,<ref name="pronic number" /> semi-meandric number<ref>{{Cite web|url=https://oeis.org/A000682|title=Sloane's A000682 : Semimeanders|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
:'''1407''' = 38<sup>2</sup> - 38 + 1 = H<sub>38</sub> (the 38th Hogben number)<ref name="auto77"/>
:'''1408''' = maximal number of regions the plane is divided into by drawing 38 circles<ref name="auto27"/>
:'''1409''' = [[Super-prime|super-prime]], Sophie Germain prime,<ref name="Sophie Germain" /> smallest number whose eighth power is the sum of 8 eighth powers, Proth prime<ref name="Proth prime" />
:'''1410''' = denominator of the 46th [[Bernoulli number]]<ref>{{cite OEIS|A002445|Denominators of Bernoulli numbers B_{2n}}}</ref>
:'''1411''' = LS(41)<ref name="ReferenceD">{{cite OEIS|A045918|Describe n. Also called the "Say What You See" or "Look and Say" sequence LS(n)}}</ref>
:'''1412''' = LS(42)<ref name="ReferenceD"/>
:'''1413''' = LS(43)<ref name="ReferenceD"/>
:'''1414''' = smallest composite that when added to sum of prime factors reaches a prime after 27 iterations<ref name="auto37">{{cite OEIS|A050710|Smallest composite that when added to sum of prime factors reaches a prime after n iterations}}</ref>
:'''1415''' = the Mahonian number: T(8, 8)<ref name="A008302" />
:'''1416''' = LS(46)<ref name="ReferenceD"/>
:'''1417''' = number of partitions of 32 in which the number of parts divides 32<ref name="auto63">{{cite OEIS|A067538|Number of partitions of n in which the number of parts divides n}}</ref>
:'''1418''' = smallest x such that M(x) = 13, where M() is [[Mertens function]]<ref name="ReferenceC"/>
:'''1419''' = [[Zeisel number]]<ref name="Zeisel number">{{Cite web|url=https://oeis.org/A051015|title=Sloane's A051015 : Zeisel numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
:'''1420''' = Number of partitions of 56 into prime parts
:'''1421''' = maximum dimension of Euclidean spaces which suffice for every smooth compact Riemannian 29-manifold to be realizable as a sub-manifold<ref name="ReferenceE">{{cite OEIS|A059845|n*(3*n + 11)/2}}</ref>
:'''1422''' = number of partitions of 15 with two parts marked<ref>{{cite OEIS|A000097|Number of partitions of n if there are two kinds of 1's and two kinds of 2's}}</ref>
:'''1423''' = 200 + 1223 and the 200th prime is 1223<ref name="auto47">{{cite OEIS|A061068|Primes which are the sum of a prime and its subscript}}</ref> Also Used as a Hate symbol
:'''1424''' = number of nonnegative solutions to x<sup>2</sup> + y<sup>2</sup> ≤ 42<sup>2</sup><ref name="auto65"/>
:'''1425''' = [[Self-descriptive number|self-descriptive number]] in base 5
:'''1426''' = sum of totient function for first 68 integers, pentagonal number,<ref name="Pentagonal number" /> number of strict partions of 42<ref name="auto20"/>
:'''1427''' = [[Twin prime|twin prime]] together with 1429<ref>{{cite OEIS|A001359|Lesser of twin primes}}</ref>
:'''1428''' = number of complete ternary trees with 6 internal nodes, or 18 edges<ref>{{cite OEIS|A001764|binomial(3*n,n)/(2*n+1) (enumerates ternary trees and also noncrossing trees)}}</ref>
:'''1429''' = number of partitions of 53 such that the smallest part is greater than or equal to number of parts<ref name="auto75"/>
:'''1430''' = [[Catalan number]]<ref>{{Cite web|url=https://oeis.org/A000108|title=Sloane's A000108 : Catalan numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
:'''1431''' = triangular number,<ref name="Triangular number" /> hexagonal number<ref name="Hexagonal number" />
:'''1432''' = member of Padovan sequence<ref name="Padovan sequence" />
:'''1433''' = [[Super-prime|super-prime]], Honaker prime,<ref name="auto39"/> typical port used for remote connections to [[Software:Microsoft SQL Server|Microsoft SQL Server]] [[Database|database]]s
:'''1434''' = rounded volume of a regular tetrahedron with edge length 23<ref name="auto88">{{cite OEIS|A071399|Rounded volume of a regular tetrahedron with edge length n}}</ref>
:'''1435''' = [[Vampire number|vampire number]];<ref name="Vampire number" /> the standard railway gauge in millimetres, equivalent to {{convert|4|ft|8+1/2|in}}
:'''1436''' = discriminant of a totally real cubic field<ref name="ReferenceF">{{cite OEIS|A006832|Discriminants of totally real cubic fields}}</ref>
:'''1437''' = smallest number of complexity 20: smallest number requiring 20 1's to build using +, * and ^<ref name="auto49">{{cite OEIS|A003037|Smallest number of complexity n: smallest number requiring n 1's to build using +, * and ^}}</ref>
:'''1438''' = k such that 5 × 2<sup>k</sup> - 1 is prime<ref name="auto69"/>
:'''1439''' = Sophie Germain prime,<ref name="Sophie Germain" /> safe prime<ref name="Safe primes" />
:'''1440''' = a [[Highly totient number|highly totient number]]<ref name="highly totient" /> and a 481-gonal number. Also, the number of [[Minute|minute]]s in one day, the blocksize of a standard {{sfrac|3|1|2}} [[Floppy disk|floppy disk]], and the horizontal resolution of WXGA(II) computer displays
:'''1441''' = star number<ref name="Centered 12-gonal numbers" />
:'''1442''' = number of parts in all partitions of 31 into distinct parts<ref name="auto46"/>
:'''1443''' = the sum of the second trio of three-digit [[Permutable prime|permutable prime]]s in [[Decimal|decimal]]: 337, 373, and 733. Also the number of edges in the join of two cycle graphs, both of order [[37 (number)|37]]<ref name="auto89"/>
:'''1444''' = 38<sup>2</sup>, smallest [[Pandigital number|pandigital number]] in [[Roman numerals]]
:'''1445''' = <math>\sum_{k=0}^3 \left( \binom{3}{k} \times \binom{3+k}{k} \right) ^2</math><ref>{{cite OEIS|A005259|Apery (Apéry) numbers: Sum_0^n (binomial(n,k)*binomial(n+k,k))^2}}</ref>
:'''1446''' = number of points on surface of octahedron with edgelength 19<ref name="auto61"/>
:'''1447''' = [[Super-prime|super-prime]], [[Happy number|happy number]]
:'''1448''' = number k such that phi(prime(k)) is a square<ref name="auto55">{{cite OEIS|A062325|Numbers k for which phi(prime(k)) is a square}}</ref>
:'''1449''' = Stella octangula number
:'''1450''' = σ<sub>2</sub>(34): sum of squares of divisors of 34<ref name="auto76"/>
:'''1451''' = Sophie Germain prime<ref name="Sophie Germain" />
:'''1452''' = first Zagreb index of the complete graph K<sub>12</sub><ref name="auto100">{{cite OEIS|A011379|n^2*(n+1)}}</ref>
:'''1453''' = [[Sexy prime]] with 1459
:'''1454''' = 3 × 22<sup>2</sup> + 2 = number of points on surface of square pyramid of side-length 22<ref name="auto58">{{cite OEIS|A005918|Number of points on surface of square pyramid: 3*n^2 + 2 (n>0)}}</ref>
:'''1455''' = k such that geometric mean of phi(k) and sigma(k) is an integer<ref name="auto68">{{cite OEIS|A011257|Geometric mean of phi(n) and sigma(n) is an integer}}</ref>
:'''1456''' = number of regions in regular 15-gon with all diagonals drawn<ref>{{cite OEIS|A007678|Number of regions in regular n-gon with all diagonals drawn}}</ref>
:'''1457''' = 2 × 27<sup>2</sup> − 1 = a [https://oeis.org/A056220/a056220.jpg twin square]<ref name="auto83">{{cite OEIS|A056220|2*n^2 - 1}}</ref>
:'''[[1458 (number)|1458]]''' = [[Hadamard's maximal determinant problem|maximum determinant]] of an 11 by 11 matrix of zeroes and ones, 3-smooth number (2×3<sup>6</sup>)
:'''1459''' = Sexy prime with 1453, sum of nine consecutive primes (139 + 149 + 151 + 157 + 163 + 167 + 173 + 179 + 181), [[Pierpont prime|pierpont prime]]
:'''1460''' = The number of years that would have to pass in the [[Julian calendar]] in order to accrue a full year's worth of leap days.
:'''1461''' = number of partitions of 38 into prime power parts<ref name="auto87"/>
:'''1462''' = (35 - 1) × (35 + 8) = the first Zagreb index of the wheel graph with 35 vertices<ref>{{cite OEIS|A028569|n*(n + 9)}}</ref>
:'''1463''' = total number of parts in all partitions of 16<ref name="auto16"/>
:'''1464''' = rounded total surface area of a regular icosahedron with edge length 13<ref>{{cite OEIS|A071398|Rounded total surface area of a regular icosahedron with edge length n}}</ref>
:'''1465''' = 5-[[Knödel number]]<ref name="auto14"/>
:'''1466''' = <math>\sum_{k=1}^{256} d(k)</math>, where <math>d(k)</math> = number of divisors of <math>k</math><ref>{{cite OEIS|A085831|Sum_1^{2^n} d(k) where d(k) is the number of divisors of k (A000005)}}</ref>
:'''1467''' = number of partitions of 39 with zero crank<ref>{{cite OEIS|A064410|Number of partitions of n with zero crank}}</ref>
:'''1468''' = number of polyhexes with 11 cells that tile the plane by translation<ref>{{cite OEIS|A075207|Number of polyhexes with n cells that tile the plane by translation}}</ref>
:'''1469''' = octahedral number,<ref name="Octahedral number" /> highly cototient number<ref name="highly cototient" />
:'''1470''' = pentagonal pyramidal number,<ref name="Pentagonal pyramidal number">{{Cite web|url=https://oeis.org/A002411|title=Sloane's A002411 : Pentagonal pyramidal numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> sum of totient function for first 69 integers
:'''1471''' = [[Super-prime|super-prime]], centered heptagonal number<ref name="centered heptagonal number" />
:'''1472''' = number of overpartitions of 15<ref>{{cite OEIS|A015128|Number of overpartitions of n: an overpartition of n is an ordered sequence of nonincreasing integers that sum to n, where the first occurrence of each integer may be overlined}}</ref>
:'''1473''' = [https://oeis.org/A144391/a144391.jpg cropped hexagone]<ref name="auto44"/>
:'''1474''' = <math>\frac{44(44 + 1)}{2} + \frac{44^2}{4}</math>: triangular number plus quarter square (i.e., A000217(44) + A002620(44))<ref>{{cite OEIS|A006578|Triangular numbers plus quarter squares: n*(n+1)/2 + floor(n^2/4) (i.e., A000217(n) + A002620(n))}}</ref>
:'''1475''' = number of partitions of 33 into parts each of which is used a different number of times<ref name="ReferenceG">{{cite OEIS|A098859|Number of partitions of n into parts each of which is used a different number of times}}</ref>
:'''1476''' = coreful perfect number<ref name="auto31">{{cite OEIS|A307958|Coreful perfect numbers}}</ref>
:'''1477''' = 7-Knödel number<ref name="auto21"/>
:'''1478''' = total number of largest parts in all compositions of 11<ref>{{cite OEIS|A097979|Total number of largest parts in all compositions of n}}</ref>
:'''1479''' = number of planar partitions of 12<ref>{{cite OEIS|A000219|Number of planar partitions (or plane partitions) of n}}</ref>
:'''1480''' = sum of the first 29 primes
:'''1481''' = Sophie Germain prime<ref name="Sophie Germain" />
:'''1482''' = pronic number,<ref name="pronic number" /> number of unimodal compositions of 15 where the maximal part appears once<ref>{{cite OEIS|A006330|Number of corners, or planar partitions of n with only one row and one column}}</ref>
:'''1483''' = 39<sup>2</sup> - 39 + 1 = H<sub>39</sub> (the 39th Hogben number)<ref name="auto77"/>
:'''1484''' = maximal number of regions the plane is divided into by drawing 39 circles<ref name="auto27"/>
:'''1485''' = triangular number
:'''1486''' = number of strict solid partitions of 19<ref name="auto43"/>
:'''1487''' = safe prime<ref name="Safe primes" />
:'''1488''' = triangular matchstick number<ref name="auto5"/>
:'''1489''' = centered triangular number<ref name="auto52"/>
:'''1490''' = tetranacci number<ref>{{Cite web|url=https://oeis.org/A000078|title=Sloane's A000078 : Tetranacci numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
:'''1491''' = nonagonal number,<ref name="Nonagonal number" /> Mertens function zero
:'''1492''' = discriminant of a totally real cubic field,<ref name="ReferenceF"/> Mertens function zero
:'''1493''' = Stern prime<ref name="Stern prime" />
:'''1494''' = sum of totient function for first 70 integers
:'''1495''' = 9###<ref>{{cite OEIS|A114411|Triple primorial n###}}</ref>
:'''1496''' = square pyramidal number<ref name="Square pyramidal numbers" />
:'''1497''' = skiponacci number<ref name="auto25"/>
:'''1498''' = number of flat partitions of 41<ref name="auto26">{{cite OEIS|A034296|Number of flat partitions of n}}</ref>
:'''1499''' = Sophie Germain prime,<ref name="Sophie Germain" /> [[Super-prime|super-prime]]

=== 1500 to 1599 ===

:'''1500''' = hypotenuse in three different Pythagorean triangles<ref name="auto101">{{cite OEIS|A084647|Hypotenuses for which there exist exactly 3 distinct integer triangles}}</ref>
:'''1501''' = centered pentagonal number<ref name="Centered pentagonal" />
:'''1502''' = number of pairs of consecutive integers x, x+1 such that all prime factors of both x and x+1 are at most 47<ref name="auto80">{{cite OEIS|A002071|Number of pairs of consecutive integers x, x+1 such that all prime factors of both x and x+1 are at most the n-th prime}}</ref>
:'''1503''' = least number of triangles of the [[Spiral of Theodorus]] to complete 12 revolutions<ref name="auto85"/>
:'''1504''' = primitive abundant number ([[Abundant number|abundant number]] all of whose proper divisors are deficient numbers)<ref name="auto92"/>
:'''1505''' = number of integer partitions of 41 with distinct differences between successive parts<ref>{{cite OEIS|A325325|Number of integer partitions of n with distinct differences between successive parts}}</ref>
:'''1506''' = number of Golomb partitions of 28<ref>{{cite OEIS|A325858|Number of Golomb partitions of n}}</ref>
:'''1507''' = number of partitions of 32 that do not contain 1 as a part<ref name="auto8"/>
:'''1508''' = heptagonal pyramidal number<ref name="auto82"/>
:'''1509''' = pinwheel number<ref name="Pinwheel" />
:'''[[1510 (number)|1510]]''' = [[Deficient number|deficient number]], [[Odious number|odious number]]
:'''1511''' = Sophie Germain prime,<ref name="Sophie Germain" /> balanced prime<ref name="Balanced prime" />
:'''1512''' = k such that geometric mean of phi(k) and sigma(k) is an integer<ref name="auto68"/>
:'''1513''' = centered square number<ref name="Centered square numbers" />
:'''1514''' = sum of first 44 composite numbers<ref name="auto94"/>
:'''1515''' = maximum dimension of Euclidean spaces which suffice for every smooth compact Riemannian 30-manifold to be realizable as a sub-manifold<ref name="ReferenceE"/>
:'''1516''' = <math>\left \lfloor 9^\frac{10}{3} \right \rfloor </math><ref>{{cite OEIS|A018000|Powers of cube root of 9 rounded down}}</ref>
:'''1517''' = number of lattice points inside a circle of radius 22<ref name="auto22"/>
:'''1518''' = sum of first 32 semiprimes,<ref>{{cite OEIS|A062198|Sum of first n semiprimes}}</ref> Mertens function zero
:'''1519''' = number of polyhexes with 8 cells,<ref>{{cite OEIS|A038147|Number of polyhexes with n cells}}</ref> Mertens function zero
:'''1520''' = pentagonal number,<ref name="Pentagonal number" /> Mertens function zero, forms a Ruth–Aaron pair with 1521 under second definition
:'''1521''' = 39<sup>2</sup>, Mertens function zero, centered octagonal number,<ref name="Centered octagonal number" /> forms a Ruth–Aaron pair with 1520 under second definition
:'''1522''' = k such that 5 × 2<sup>k</sup> - 1 is prime<ref name="auto69"/>
:'''1523''' = [[Super-prime|super-prime]], Mertens function zero, safe prime,<ref name="Safe primes" /> member of the Mian–Chowla sequence<ref name=Mian-Chowla />
:'''1524''' = Mertens function zero, k such that geometric mean of phi(k) and sigma(k) is an integer<ref name="auto68"/>
:'''1525''' = heptagonal number,<ref name="heptagonal number" /> Mertens function zero
:'''1526''' = number of conjugacy classes in the alternating group A<sub>27</sub><ref name="auto33">{{cite OEIS|A000702|number of conjugacy classes in the alternating group A_n}}</ref>
:'''1527''' = number of 2-dimensional partitions of 11,<ref>{{cite OEIS|A001970|Functional determinants; partitions of partitions; Euler transform applied twice to all 1's sequence}}</ref> Mertens function zero
:'''1528''' = Mertens function zero, rounded total surface area of a regular octahedron with edge length 21<ref>{{cite OEIS|A071396|Rounded total surface area of a regular octahedron with edge length n}}</ref>
:'''1529''' = composite de Polignac number<ref name="auto53"/>
:'''1530''' = [[Vampire number|vampire number]]<ref name="Vampire number" />
:'''1531''' = prime number, centered decagonal number, Mertens function zero
:'''1532''' = number of series-parallel networks with 9 unlabeled edges,<ref>{{cite OEIS|A000084|Number of series-parallel networks with n unlabeled edges. Also called yoke-chains by Cayley and MacMahon}}</ref> Mertens function zero
:'''1533''' = 21 × 73 = 21 × 21st prime<ref name="cite OEIS|A033286|n * primen"/>
:'''1534''' = number of achiral integer partitions of 50<ref name="auto64"/>
:'''1535''' = [[Thabit number]]
:'''1536''' = a common size of [[Engineering:Microplate|microplate]], 3-smooth number (2<sup>9</sup>×3), number of threshold functions of exactly 4 variables<ref>{{cite OEIS|A000615|Threshold functions of exactly n variables}}</ref>
:'''1537''' = Keith number,<ref name="Keith number" /> Mertens function zero
:'''1538''' = number of surface points on a cube with edge-length 17<ref name="A005897">{{cite OEIS|A005897|6*n^2 + 2 for n > 0}}</ref>
:'''1539''' = maximal number of pieces that can be obtained by cutting an annulus with 54 cuts<ref name="auto73"/>
:'''1540''' = triangular number, hexagonal number,<ref name="Hexagonal number" /> decagonal number,<ref name="Decagonal" /> tetrahedral number<ref name="Leyland number" />
:'''1541''' = octagonal number<ref name="auto17"/>
:'''1542''' = k such that 2^k starts with k<ref>{{cite OEIS|A100129|Numbers k such that 2^k starts with k}}</ref>
:'''1543''' = prime dividing all Fibonacci sequences,<ref>{{cite OEIS|A000057|Primes dividing all Fibonacci sequences}}</ref> Mertens function zero
:'''1544''' = Mertens function zero, number of partitions of integer partitions of 17 where all parts have the same length<ref>{{cite OEIS|A319066|Number of partitions of integer partitions of n where all parts have the same length}}</ref>
:'''1545''' = number of reversible string structures with 9 beads using exactly three different colors<ref>{{cite OEIS|A056327|Number of reversible string structures with n beads using exactly three different colors}}</ref>
:'''1546''' = number of 5 X 5 binary matrices with at most one 1 in each row and column,<ref>{{cite OEIS|A002720|Number of partial permutations of an n-set; number of n X n binary matrices with at most one 1 in each row and column}}</ref> Mertens function zero
:'''1547''' = hexagonal pyramidal number
:'''1548''' = coreful perfect number<ref name="auto31"/>
:'''1549''' = de Polignac prime<ref name="auto67">{{cite OEIS|A065381|Primes not of the form p + 2^k}}</ref>
:'''1550''' = <math>\frac {31 \times (3 \times 31 + 7)}{2}</math> = number of cards needed to build a 31-tier house of cards with a flat, one-card-wide roof<ref>{{cite OEIS|A140090|n*(3*n + 7)/2}}</ref>
:'''1551''' = 6920 - 5369 = A169952(24) - A169952(23) = A169942(24) = number of Golomb rulers of length 24<ref>{{cite OEIS|A169942|Number of Golomb rulers of length n}}</ref><ref>{{cite OEIS|A169952|Second entry in row n of triangle in A169950}}</ref>
:'''1552''' = Number of partitions of 57 into prime parts
:'''1553''' = 509 + 521 + 523 = a prime that is the sum of three consecutive primes<ref>{{cite OEIS|A034962|Primes that are the sum of three consecutive primes}}</ref>
:'''1554''' = 2 × 3 × 7 × 37 = product of four distinct primes<ref>{{cite OEIS|A046386|Products of four distinct primes}}</ref>
:'''1555'''<sup>2</sup> divides 6<sup>1554</sup><ref>{{cite OEIS|A127106|Numbers n such that n^2 divides 6^n-1}}</ref>
:'''1556''' = sum of the squares of the first nine primes
:'''1557''' = number of graphs with 8 nodes and 13 edges<ref name="auto78">{{cite OEIS|A008406|Triangle T(n,k) read by rows, giving number of graphs with n nodes and k edges)}}</ref>
:'''1558''' = number k such that k<sup>64</sup> + 1 is prime
:'''1559''' = Sophie Germain prime<ref name="Sophie Germain" />
:'''1560''' = pronic number<ref name="pronic number" />
:'''1561''' = a centered octahedral number,<ref name="auto7"/> number of series-reduced trees with 19 nodes<ref>{{cite OEIS|A000014|Number of series-reduced trees with n nodes}}</ref>
:'''1562''' = maximal number of regions the plane is divided into by drawing 40 circles<ref name="auto27"/>
:'''1563''' = <math>\sum_{k=1}^{50} \frac{50}{\gcd(50,k)}</math><ref>{{cite OEIS|A057660|Sum_{1..n} n/gcd(n,k)}}</ref>
:'''1564''' = sum of totient function for first 71 integers
:'''1565''' = <math>\sqrt{1036^2+1173^2}</math> and <math>1036+1173=47^2</math><ref>{{cite OEIS|A088319|Ordered hypotenuses of primitive Pythagorean triangles having legs that add up to a square}}</ref>
:'''1566''' = number k such that k<sup>64</sup> + 1 is prime
:'''1567''' = number of partitions of 24 with at least one distinct part<ref name="auto66"/>
:'''1568''' = [[Achilles number]]<ref name="Achilles">{{cite OEIS|A052486|Achilles numbers}}</ref>
:'''1569''' = 2 × 28<sup>2</sup> + 1 = number of different 2 × 2 determinants with integer entries from 0 to 28<ref name="auto32"/>
:'''1570''' = 2 × 28<sup>2</sup> + 2 = number of points on surface of tetrahedron with edgelength 28<ref name="auto59"/>
:'''1571''' = Honaker prime<ref name="auto39"/>
:'''1572''' = member of the Mian–Chowla sequence<ref name=Mian-Chowla />
:'''1573''' = discriminant of a totally real cubic field<ref name="ReferenceF"/>
:'''1574'''<sup>256</sup> + 1 is prime<ref>{{cite OEIS|A056995|Numbers k such that k^256 + 1 is prime}}</ref>
:'''1575''' = odd [[Abundant number|abundant number]],<ref>{{Cite web|url=https://oeis.org/A005231|title=Sloane's A005231 : Odd abundant numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> sum of the nontriangular numbers between successive triangular numbers, number of partitions of 24<ref name="auto35"/>
:'''1576'''<sup>14</sup> == 1 (mod 15^2)<ref>{{cite OEIS|A056026|Numbers k such that k^14 is congruent with 1 (mod 15^2)}}</ref>
:'''1577''' = sum of the quadratic residues of 83<ref>{{cite OEIS|A076409|Sum of the quadratic residues of prime(n)}}</ref>
:'''1578''' = sum of first 45 composite numbers<ref name="auto94"/>
:'''1579''' = number of partitions of 54 such that the smallest part is greater than or equal to number of parts<ref name="auto75"/>
:'''1580''' = number of achiral integer partitions of 51<ref name="auto64"/>
:'''1581''' = number of edges in the [[:File:Hexagonal triangle.png|hexagonal triangle]] T(31)<ref name="auto60"/>
:'''1582''' = a number such that the integer triangle [A070080(1582), A070081(1582), A070082(1582)] has an integer area<ref>{{cite OEIS|A070142|Numbers n such that [A070080(n), A070081(n), A070082(n)] is an integer triangle with integer area}}</ref>
:'''1583''' = Sophie Germain prime
:'''1584''' = triangular matchstick number<ref name="auto5"/>
:'''1585''' = Riordan number, centered triangular number<ref name="auto52"/>
:'''1586''' = area of the 23rd [https://oeis.org/A080663/a080663.jpg conjoined trapezoid]<ref name="auto13"/>
:'''1587''' = 3 × 23<sup>2</sup> = number of edges of a complete tripartite graph of order 69, K<sub>23,23,23</sub><ref>{{cite OEIS|A033428|3*n^2}}</ref>
:'''1588''' = sum of totient function for first 72 integers
:'''1589''' = composite de Polignac number<ref name="auto53"/>
:'''1590''' = rounded volume of a regular icosahedron with edge length 9<ref>{{cite OEIS|A071402|Rounded volume of a regular icosahedron with edge length n}}</ref>
:'''1591''' = rounded volume of a regular octahedron with edge length 15<ref name="auto84"/>
:'''1592''' = sum of all divisors of the first 36 odd numbers<ref>{{cite OEIS|A326123|a(n) is the sum of all divisors of the first n odd numbers}}</ref>
:'''1593''' = sum of the first 30 primes
:'''1594''' = minimal cost of maximum height Huffman tree of size 17<ref>{{cite OEIS|A006327|Fibonacci(n) - 3. Number of total preorders}}</ref>
:'''1595''' = number of non-isomorphic set-systems of weight 10
:'''1596''' = triangular number
:'''1597''' = [[Fibonacci prime]],<ref>{{Cite web|url=https://oeis.org/A000045|title=Sloane's A000045 : Fibonacci numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> Markov prime,<ref name="Markov number" /> [[Super-prime|super-prime]], [[Emirp|emirp]]
:'''1598''' = number of unimodular 2 × 2 matrices having all terms in {0,1,...,25}<ref name="auto54"/>
:'''1599''' = number of edges in the join of two cycle graphs, both of order 39<ref name="auto89"/>

=== 1600 to 1699 ===

:'''1600''' = 40<sup>2</sup>, structured great rhombicosidodecahedral number,<ref>{{cite OEIS|A100145|Structured great rhombicosidodecahedral numbers}}</ref> repdigit in base 7 (4444<sub>7</sub>), street number on Pennsylvania Avenue of the White House, length in meters of a common High School Track Event, perfect score on SAT (except from 2005 to 2015)
:'''1601''' = Sophie Germain prime, Proth prime,<ref name="Proth prime" /> the novel ''1601 (Mark Twain)''
:'''1602''' = number of points on surface of octahedron with edgelength 20<ref name="auto61"/>
:'''1603''' = number of partitions of 27 with nonnegative rank<ref name="auto18">{{cite OEIS|A064174|Number of partitions of n with nonnegative rank}}</ref>
:'''1604''' = number of compositions of 22 into prime parts<ref>{{cite OEIS|A023360|Number of compositions of n into prime parts}}</ref>
:'''1605''' = number of polyominoes consisting of 7 regular octagons<ref>{{cite OEIS|A103473|Number of polyominoes consisting of 7 regular unit n-gons}}</ref>
:'''1606''' = enneagonal pyramidal number<ref>{{cite OEIS|A007584|9-gonal (or enneagonal) pyramidal numbers}}</ref>
:'''1607''' = member of prime triple with 1609 and 1613<ref>{{cite OEIS|A022004|Initial members of prime triples (p, p+2, p+6)}}</ref>
:'''1608''' = <math>\sum_{k=1}^{44} \sigma(k)</math><ref name="auto38"/>
:'''1609''' = [https://oeis.org/A144391/a144391.jpg cropped hexagonal number]<ref name="auto44"/>
:'''1610''' = number of strict partions of 43<ref name="auto20"/>
:'''1611''' = number of rational numbers which can be constructed from the set of integers between 1 and 51<ref name="auto56"/>
:'''1612''' = maximum dimension of Euclidean spaces which suffice for every smooth compact Riemannian 31-manifold to be realizable as a sub-manifold<ref name="ReferenceE"/>
:'''1613''', 1607 and 1619 are all primes<ref>{{cite OEIS|A006489|Numbers k such that k-6, k, and k+6 are primes}}</ref>
:'''1614''' = number of ways of refining the partition 8^1 to get 1^8<ref>{{cite OEIS|A213427|Number of ways of refining the partition n^1 to get 1^n}}</ref>
:'''1615''' = composite number such that the square mean of its prime factors is a nonprime integer<ref>{{cite OEIS|A134602|Composite numbers such that the square mean of their prime factors is a nonprime integer (where the prime factors are taken with multiplicity and the square mean of c and d is sqrt((c^2+d^2)/2))}}</ref>
:'''1616''' = <math>\frac{16(16^2 + 3 \times 16 - 1)}{3}</math> = number of monotonic triples (x,y,z) in {1,2,...,16}<sup>3</sup><ref>{{cite OEIS|A084990|n*(n^2+3*n-1)/3}}</ref>
:'''1617''' = pentagonal number<ref name="Pentagonal number" />
:'''1618''' = centered heptagonal number<ref name="centered heptagonal number" />
:'''1619''' = [[Palindromic prime|palindromic prime]] in binary, safe prime<ref name="Safe primes" />
:'''1620''' = 809 + 811: sum of twin prime pair<ref name="auto48"/>
:'''1621''' = [[Super-prime|super-prime]], pinwheel number<ref name="Pinwheel" />
:'''1622''' = semiprime of the form prime + 1<ref>{{cite OEIS|A077068|Semiprimes of the form prime + 1}}</ref>
:'''1623''' is not the sum of two triangular numbers and a fourth power<ref>{{cite OEIS|A115160|Numbers that are not the sum of two triangular numbers and a fourth power}}</ref>
:'''1624''' = number of squares in the [[Aztec diamond]] of order 28<ref name="auto36">{{cite OEIS|A046092|4 times triangular numbers}}</ref>
:'''1625''' = centered square number<ref name="Centered square numbers" />
:'''1626''' = centered pentagonal number<ref name="Centered pentagonal" />
:'''1627''' = prime and 2 × 1627 - 1 = 3253 is also prime<ref>{{cite OEIS|A005382|Primes p such that 2p-1 is also prime}}</ref>
:'''1628''' = centered pentagonal number<ref name="Centered pentagonal" />
:'''1629''' = rounded volume of a regular tetrahedron with edge length 24<ref name="auto88"/>
:'''1630''' = number k such that k^64 + 1 is prime
:'''1631''' = <math>\sum_{k=0}^{5} (k+1)! \binom{5}{k}</math><ref>{{cite OEIS|A001339|Sum_{0..n} (k+1)! binomial(n,k)}}</ref>
:'''1632''' = number of acute triangles made from the vertices of a regular 18-polygon<ref>{{cite OEIS|A007290|2*binomial(n,3)}}</ref>
:'''1633''' = star number<ref name="Centered 12-gonal numbers" />
:'''1634''' = [[Narcissistic number]] in base 10
:'''1635''' = number of partitions of 56 whose reciprocal sum is an integer<ref>{{cite OEIS|A058360|Number of partitions of n whose reciprocal sum is an integer}}</ref>
:'''1636''' = number of nonnegative solutions to x<sup>2</sup> + y<sup>2</sup> ≤ 45<sup>2</sup><ref name="auto65"/>
:'''1637''' = prime island: least prime whose adjacent primes are exactly 30 apart<ref>{{cite OEIS|A046931|Prime islands: least prime whose adjacent primes are exactly 2n apart}}</ref>
:'''1638''' = [[Harmonic divisor number|harmonic divisor number]],<ref>{{Cite web|url=https://oeis.org/A001599|title=Sloane's A001599 : Harmonic or Ore numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> 5 × 2<sup>1638</sup> - 1 is prime<ref name="auto69"/>
:'''1639''' = nonagonal number<ref name="Nonagonal number" />
:'''1640''' = pronic number<ref name="pronic number" />
:'''1641''' = 41<sup>2</sup> - 41 + 1 = H<sub>41</sub> (the 41st Hogben number)<ref name="auto77"/>
:'''1642''' = maximal number of regions the plane is divided into by drawing 41 circles<ref name="auto27"/>
:'''1643''' = sum of first 46 composite numbers<ref name="auto94"/>
:'''1644''' = 821 + 823: sum of twin prime pair<ref name="auto48"/>
:'''1645''' = number of 16-celled pseudo still lifes in Conway's Game of Life, up to rotation and reflection<ref>{{cite OEIS|A056613|Number of n-celled pseudo still lifes in Conway's Game of Life, up to rotation and reflection}}</ref>
:'''1646''' = number of graphs with 8 nodes and 14 edges<ref name="auto78"/>
:'''1647''' and 1648 are both divisible by cubes<ref>{{cite OEIS|A068140|Smaller of two consecutive numbers each divisible by a cube greater than one}}</ref>
:'''1648''' = number of partitions of 34<sup>3</sup> into distinct cubes<ref>{{cite OEIS|A030272|Number of partitions of n^3 into distinct cubes}}</ref>
:'''1649''' = highly cototient number,<ref name="highly cototient" /> Leyland number<ref name="Leyland number" />
:'''1650''' = number of cards to build an 33-tier house of cards<ref name="auto45"/>
:'''1651''' = heptagonal number<ref name="heptagonal number" />
:'''1652''' = number of partitions of 29 into a prime number of parts<ref name="auto70"/>
:'''1653''' = triangular number, hexagonal number,<ref name="Hexagonal number" /> number of lattice points inside a circle of radius 23<ref name="auto22"/>
:'''1654''' = number of partitions of 42 into divisors of 42<ref>{{cite OEIS|A018818|Number of partitions of n into divisors of n}}</ref>
:'''1655''' = rounded volume of a regular dodecahedron with edge length 6<ref>{{cite OEIS|A071401|Rounded volume of a regular dodecahedron with edge length n}}</ref>
:'''1656''' = 827 + 829: sum of twin prime pair<ref name="auto48"/>
:'''1657''' = [[Cuban prime|cuban prime]],<ref name="Cuban Prime">{{Cite web|url=https://oeis.org/A002407|title=Sloane's A002407 : Cuban primes|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> prime of the form 2p-1
:'''1658''' = smallest composite that when added to sum of prime factors reaches a prime after 25 iterations<ref name="auto37"/>
:'''1659''' = number of rational numbers which can be constructed from the set of integers between 1 and 52<ref name="auto56"/>
:'''1660''' = sum of totient function for first 73 integers
:'''1661''' = 11 × 151, palindrome that is a product of two palindromic primes<ref name="auto29"/>
:'''1662''' = number of partitions of 49 into pairwise relatively prime parts<ref name="auto71"/>
:'''1663''' = a prime number and 5<sup>1663</sup> - 4<sup>1663</sup> is a 1163-digit prime number<ref>{{cite OEIS|A059802|Numbers k such that 5^k - 4^k is prime}}</ref>
:'''1664''' = k such that k, k+1 and k+2 are sums of 2 squares<ref name="auto97">{{cite OEIS|A082982|Numbers k such that k, k+1 and k+2 are sums of 2 squares}}</ref>
:'''1665''' = centered tetrahedral number<ref name="auto42"/>
:'''1666''' = largest efficient [[Pandigital number|pandigital number]] in [[Roman numerals]] (each symbol occurs exactly once)
:'''1667''' = 228 + 1439 and the 228th prime is 1439<ref name="auto47"/>
:'''1668''' = number of partitions of 33 into parts all relatively prime to 33<ref>{{cite OEIS|A057562|Number of partitions of n into parts all relatively prime to n}}</ref>
:'''1669''' = [[Super-prime|super-prime]], smallest prime with a gap of exactly 24 to the next prime<ref>{{cite OEIS|A000230|smallest prime p such that there is a gap of exactly 2n between p and next prime}}</ref>
:'''1670''' = number of compositions of 12 such that at least two adjacent parts are equal<ref>{{cite OEIS|A261983|Number of compositions of n such that at least two adjacent parts are equal}}</ref>
:'''1671''' divides the sum of the first 1671 composite numbers<ref>{{cite OEIS|A053781|Numbers k that divide the sum of the first k composite numbers}}</ref>
:'''1672''' = 41<sup>2</sup> - 3<sup>2</sup>, the only way to express 1672 as a difference of prime squares<ref name="auto96"/>
:'''1673''' = RMS number<ref>{{cite OEIS|A140480|RMS numbers: numbers n such that root mean square of divisors of n is an integer}}</ref>
:'''1674''' = k such that geometric mean of phi(k) and sigma(k) is an integer<ref name="auto68"/>
:'''1675''' = Kin number<ref>{{cite OEIS|A023108|Positive integers which apparently never result in a palindrome under repeated applications of the function A056964(x)}}</ref>
:'''1676''' = number of partitions of 34 into parts each of which is used a different number of times<ref name="ReferenceG"/>
:'''1677''' = 41<sup>2</sup> - 2<sup>2</sup>, the only way to express 1677 as a difference of prime squares<ref name="auto96"/>
:'''1678''' = n such that n<sup>32</sup> + 1 is prime<ref name="auto51"/>
:'''1679''' = highly cototient number,<ref name="highly cototient" /> semiprime (23 × 73, see also [[Astronomy:Arecibo message|Arecibo message]]), number of parts in all partitions of 32 into distinct parts<ref name="auto46"/>
:'''1680''' = highly composite number,<ref name="Highly composite" /> number of edges in the join of two cycle graphs, both of order 40<ref name="auto89"/>
:'''1681''' = 41<sup>2</sup>, smallest number yielded by the formula ''n''<sup>2</sup> + ''n'' + 41 that is not a prime; centered octagonal number<ref name="Centered octagonal number" />
:'''1682''' = and '''1683''' is a member of a Ruth–Aaron pair (first definition)
:'''1683''' = triangular matchstick number<ref name="auto5"/>
:'''1684''' = centered triangular number<ref name="auto52"/>
:'''1685''' = 5-[[Knödel number]]<ref name="auto14"/>
:'''1686''' = <math>\sum_{k=1}^{45} \sigma(k)</math><ref name="auto38"/>
:'''1687''' = 7-Knödel number<ref name="auto21"/>
:'''1688''' = number of finite connected sets of positive integers greater than one with least common multiple 72<ref>{{cite OEIS|A286518|Number of finite connected sets of positive integers greater than one with least common multiple n}}</ref>
:'''1689''' = <math>9!!\sum_{k=0}^{4} \frac{1}{2k+1}</math><ref>{{cite OEIS|A004041|Scaled sums of odd reciprocals: (2*n + 1)!!*(Sum_{0..n} 1/(2*k + 1))}}</ref>
:'''1690''' = number of compositions of 14 into powers of 2<ref>{{cite OEIS|A023359|Number of compositions (ordered partitions) of n into powers of 2}}</ref>
:'''1691''' = the same upside down, which makes it a strobogrammatic number<ref>{{cite OEIS|A000787|Strobogrammatic numbers: the same upside down}}</ref>
:'''1692''' = coreful perfect number<ref name="auto31"/>
:'''1693''' = smallest prime > 41<sup>2</sup>.<ref name="auto57"/>
:'''1694''' = number of unimodular 2 × 2 matrices having all terms in {0,1,...,26}<ref name="auto54"/>
:'''1695''' = [[Magic constant|magic constant]] of ''n'' × ''n'' normal [[Magic square|magic square]] and [[Eight queens puzzle|''n''-queens problem]] for ''n'' = 15. Number of partitions of 58 into prime parts
:'''1696''' = sum of totient function for first 74 integers
:'''1697''' = Friedlander-Iwaniec prime<ref name="auto12"/>
:'''1698''' = number of rooted trees with 47 vertices in which vertices at the same level have the same degree<ref name="auto28"/>
:'''1699''' = number of rooted trees with 48 vertices in which vertices at the same level have the same degree<ref name="auto28"/>

=== 1700 to 1799 ===

:'''1700''' = σ<sub>2</sub>(39): sum of squares of divisors of 39<ref name="auto76"/>
:'''[[1701 (number)|1701]]''' = [[Stirling numbers of the second kind|<math>\left\{ {8 \atop 4} \right\}</math>]], decagonal number, hull number of the U.S.S. Enterprise on ''Star Trek''
:'''1702''' = palindromic in 3 consecutive bases: 898<sub>14</sub>, 787<sub>15</sub>, 6A6<sub>16</sub>
:'''1703''' = 1703131131 / 1000077 and the divisors of 1703 are 1703, 131, 13 and 1<ref>{{cite OEIS|A224930|Numbers n such that n divides the concatenation of all divisors in descending order}}</ref>
:'''1704''' = sum of the squares of the parts in the partitions of 18 into two distinct parts<ref>{{cite OEIS|A294286|Sum of the squares of the parts in the partitions of n into two distinct parts}}</ref>
:'''1705''' = tribonacci number<ref>{{Cite web|url=https://oeis.org/A000073|title=Sloane's A000073 : Tribonacci numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
:'''1706''' = 1 + 4 + 16 + 64 + 256 + 1024 + 256 + 64 + 16 + 4 + 1 sum of fifth row of triangle of powers of 4<ref>{{cite OEIS|A020989|(5*4^n - 2)/3}}</ref>
:'''1707''' = number of partitions of 30 in which the number of parts divides 30<ref name="auto63"/>
:'''1708''' = 2<sup>2</sup> × 7 × 61 a number whose product of prime indices 1 × 1 × 4 × 18 is divisible by its sum of prime factors 2 + 2 + 7 + 61<ref>{{cite OEIS|A331378|Numbers whose product of prime indices is divisible by their sum of prime factors}}</ref>
:'''1709''' = first of a sequence of eight primes formed by adding [[57 (number)|57]] in the middle. 1709, 175709, 17575709, 1757575709, 175757575709, 17575757575709, 1757575757575709 and 175757575757575709 are all prime, but 17575757575757575709 = 232433 × 75616446785773
:'''1710''' = maximal number of pieces that can be obtained by cutting an annulus with 57 cuts<ref name="auto73"/>
:'''1711''' = triangular number, centered decagonal number
:'''1712''' = number of irredundant sets in the 29-cocktail party graph<ref name="auto34"/>
:'''1713''' = number of aperiodic rooted trees with 12 nodes<ref>{{cite OEIS|A301700|Number of aperiodic rooted trees with n nodes}}</ref>
:'''1714''' = number of regions formed by drawing the line segments connecting any two of the 18 perimeter points of an [https://oeis.org/A331452/a331452_20.png 3 × 6 grid of squares]<ref>{{cite OEIS|A331452|number of regions (or cells) formed by drawing the line segments connecting any two of the 2*(m+n) perimeter points of an m X n grid of squares}}</ref>
:'''1715''' = k such that geometric mean of phi(k) and sigma(k) is an integer<ref name="auto68"/>
:'''1716''' = 857 + 859: sum of twin prime pair<ref name="auto48"/>
:'''1717''' = pentagonal number<ref name="Pentagonal number" />
:'''1718''' = <math>\sum_{d|12} \binom{12}{d}</math><ref>{{cite OEIS|A056045|"Sum_{d divides n}(binomial(n,d))"}}</ref>
:'''1719''' = composite de Polignac number<ref name="auto53"/>
:'''1720''' = sum of the first 31 primes
:'''1721''' = twin prime; number of squares between 42<sup>2</sup> and 42<sup>4</sup>.<ref name="auto40"/>
:'''1722''' = [[Giuga number]],<ref>{{Cite web|url=https://oeis.org/A007850|title=Sloane's A007850 : Giuga numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> pronic number<ref name="pronic number" />
:'''1723''' = [[Super-prime|super-prime]]
:'''1724''' = maximal number of regions the plane is divided into by drawing 42 circles<ref name="auto27"/>
:'''1725''' = 47<sup>2</sup> - 22<sup>2</sup> = (prime(15))<sup>2</sup> - (nonprime(15))<sup>2</sup><ref>{{cite OEIS|A161757|(prime(n))^2 - (nonprime(n))^2}}</ref>
:'''1726''' = number of partitions of 44 into distinct and relatively prime parts<ref>{{cite OEIS|A078374|Number of partitions of n into distinct and relatively prime parts}}</ref>
:'''1727''' = area of the 24th [https://oeis.org/A080663/a080663.jpg conjoined trapezoid]<ref name="auto13"/>
:'''[[1728 (number)|1728]]''' = the quantity expressed as 1000 in [[Duodecimal|duodecimal]], that is, the cube of [[12 (number)|twelve]] (called a [[Great gross|great gross]]), and so, the number of cubic inches in a cubic foot, palindromic in base 11 (1331<sub>11</sub>) and 23 (363<sub>23</sub>)
:'''[[1729 (number)|1729]]''' = [[Taxicab number|taxicab number]], Carmichael number, Zeisel number, centered cube number, Hardy–Ramanujan number. In the decimal expansion of [[E (mathematical constant)|e]] the first time all 10 digits appear in sequence starts at the 1729th digit (or 1728th decimal place). In 1979 the rock musical ''Hair'' closed on Broadway in New York City after 1729 performances. Palindromic in bases 12, 32, 36.
:'''1730''' = 3 × 24<sup>2</sup> + 2 = number of points on surface of square pyramid of side-length 24<ref name="auto58"/>
:'''1731''' = k such that geometric mean of phi(k) and sigma(k) is an integer<ref name="auto68"/>
:'''1732''' = <math>\sum_{k=0}^5 \binom{5}{k}^k</math><ref>{{cite OEIS|A167008|Sum_{0..n} C(n,k)^k}}</ref>
:'''1733''' = Sophie Germain prime, palindromic in bases 3, 18, 19.
:'''1734''' = surface area of a cube of edge length 17<ref>{{cite OEIS|A033581|6*n^2}}</ref>
:'''1735''' = number of partitions of 55 such that the smallest part is greater than or equal to number of parts<ref name="auto75"/>
:'''1736''' = sum of totient function for first 75 integers, number of surface points on a cube with edge-length 18<ref name="A005897" />
:'''1737''' = pinwheel number<ref name="Pinwheel" />
:'''1738''' = number of achiral integer partitions of 52<ref name="auto64"/>
:'''1739''' = number of 1s in all partitions of 30 into odd parts<ref>{{cite OEIS|A036469|Partial sums of A000009 (partitions into distinct parts)}}</ref>
:'''1740''' = number of squares in the [[Aztec diamond]] of order 29<ref name="auto36"/>
:'''1741''' = [[Super-prime|super-prime]], centered square number<ref name="Centered square numbers" />
:'''1742''' = [https://mathworld.wolfram.com/PlaneDivisionbyEllipses.html number of regions] the plane is divided into by 30 ellipses<ref name="auto91"/>
:'''1743''' = [[Wiener index|wiener index]] of the [[Windmill graph|windmill graph]] D(3,21)<ref name="auto90"/>
:'''1744''' = k such that k, k+1 and k+2 are sums of 2 squares<ref name="auto97"/>
:'''1745''' = 5-[[Knödel number]]<ref name="auto14"/>
:'''1746''' = number of unit-distance graphs on 8 nodes<ref>{{cite OEIS|A350507|Number of (not necessarily connected) unit-distance graphs on n nodes}}</ref>
:'''1747''' = balanced prime<ref name="Balanced prime" />
:'''1748''' = number of partitions of 55 into distinct parts in which the number of parts divides 55<ref>{{cite OEIS|A102627|Number of partitions of n into distinct parts in which the number of parts divides n}}</ref>
:'''1749''' = number of integer partitions of 33 with no part dividing all the others<ref name="auto30"/>
:'''1750''' = hypotenuse in three different Pythagorean triangles<ref name="auto101"/>
:'''1751''' = [https://oeis.org/A144391/a144391.jpg cropped hexagone]<ref name="auto44"/>
:'''1752''' = 79<sup>2</sup> - 67<sup>2</sup>, the only way to express 1752 as a difference of prime squares<ref name="auto96"/>
:'''1753''' = [[Balanced prime|balanced prime]]<ref name="Balanced prime" />
:'''1754''' = k such that 5*2<sup>k</sup> - 1 is prime<ref name="auto69"/>
:'''1755''' = number of integer partitions of 50 whose augmented differences are distinct<ref name="auto19"/>
:'''1756''' = centered pentagonal number<ref name="Centered pentagonal" />
:'''1757''' = least number of triangles of the [[Spiral of Theodorus]] to complete 13 revolutions<ref name="auto85"/>
:'''1758''' = <math>\sum_{k=1}^{46} \sigma(k)</math><ref name="auto38"/>
:'''1759''' = de Polignac prime<ref name="auto67"/>
:'''1760''' = the number of [[Yard|yard]]s in a mile
:'''1761''' = k such that k, k+1 and k+2 are products of two primes<ref name="auto81"/>
:'''1762''' = number of binary sequences of length 12 and [http://neilsloane.com/doc/CNC.pdf curling number 2]<ref>{{cite OEIS|A216955|number of binary sequences of length n and curling number k}}</ref>
:'''1763''' = number of edges in the join of two cycle graphs, both of order 41<ref name="auto89"/>
:'''1764''' = 42<sup>2</sup>
:'''1765''' = number of stacks, or planar partitions of 15<ref>{{cite OEIS|A001523|Number of stacks, or planar partitions of n; also weakly unimodal compositions of n}}</ref>
:'''1766''' = number of points on surface of octahedron with edgelength 21<ref name="auto61"/>
:'''1767''' = σ(28<sup>2</sup>) = σ(35<sup>2</sup>)<ref>{{cite OEIS|A065764|Sum of divisors of square numbers}}</ref>
:'''1768''' = number of nonequivalent dissections of an hendecagon into 8 polygons by nonintersecting diagonals up to rotation<ref>{{cite OEIS|A220881|Number of nonequivalent dissections of an n-gon into n-3 polygons by nonintersecting diagonals up to rotation}}</ref>
:'''1769''' = maximal number of pieces that can be obtained by cutting an annulus with 58 cuts<ref name="auto73"/>
:'''1770''' = triangular number, hexagonal number,<ref name="Hexagonal number" /> Seventeen Seventy, town in Australia
:'''1771''' = tetrahedral number<ref name="Leyland number" />
:'''1772''' = centered heptagonal number,<ref name="centered heptagonal number" /> sum of totient function for first 76 integers
:'''1773''' = number of words of length 5 over the alphabet {1,2,3,4,5} such that no two even numbers appear consecutively<ref>{{cite OEIS|A154964|3*a(n-1) + 6*a(n-2)}}</ref>
:'''1774''' = number of rooted identity trees with 15 nodes and 5 leaves<ref>{{cite OEIS|A055327|Triangle of rooted identity trees with n nodes and k leaves}}</ref>
:'''1775''' = <math>\sum_{1\leq i\leq 10}prime(i)\cdot(2\cdot i-1)</math>: sum of piles of first 10 primes<ref>{{cite OEIS|A316322|Sum of piles of first n primes}}</ref>
:'''1776''' = [https://oeis.org/A045944/a045944_1.jpg square star number].<ref>{{cite OEIS|A045944|Rhombic matchstick numbers: n*(3*n+2)}}</ref> The number of pieces that could be seen in a 7 × 7 × 7× 7 Rubik's Tesseract.
:'''1777''' = smallest prime > 42<sup>2</sup>.<ref name="auto57"/>
:'''1778''' = least k >= 1 such that the remainder when 6<sup>k</sup> is divided by k is 22<ref>{{cite OEIS|A127816|least k such that the remainder when 6^k is divided by k is n}}</ref>
:'''1779''' = number of achiral integer partitions of 53<ref name="auto64"/>
:'''1780''' = number of lattice paths from (0, 0) to (7, 7) using E (1, 0) and N (0, 1) as steps that horizontally cross the diagonal y = x with even many times<ref>{{cite OEIS|A005317|(2^n + C(2*n,n))/2}}</ref>
:'''1781''' = the first 1781 digits of e form a prime<ref>{{cite OEIS|A064118|Numbers k such that the first k digits of e form a prime}}</ref>
:'''1782''' = heptagonal number<ref name="heptagonal number" />
:'''1783''' = de Polignac prime<ref name="auto67"/>
:'''1784''' = number of subsets of {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12} such that every pair of distinct elements has a different quotient<ref>{{cite OEIS|A325860|Number of subsets of {1..n} such that every pair of distinct elements has a different quotient}}</ref>
:'''1785''' = square pyramidal number,<ref name="Square pyramidal numbers" /> triangular matchstick number<ref name="auto5"/>
:'''1786''' = centered triangular number<ref name="auto52"/>
:'''1787''' = [[Super-prime|super-prime]], sum of eleven consecutive primes (137 + 139 + 149 + 151 + 157 + 163 + 167 + 173 + 179 + 181 + 191)
:'''1788''' = Euler transform of -1, -2, ..., -34<ref>{{cite OEIS|A073592|Euler transform of negative integers}}</ref>
:'''1789''' = number of wiggly sums adding to 17 (terms alternately increase and decrease or vice versa)<ref>{{cite OEIS|A025047|Alternating compositions, i.e., compositions with alternating increases and decreases, starting with either an increase or a decrease}}</ref>
:'''1790''' = number of partitions of 50 into pairwise relatively prime parts<ref name="auto71"/>
:'''1791''' = largest natural number that cannot be expressed as a sum of at most four hexagonal numbers.
:'''1792''' = [[Granville number]]
:'''1793''' = number of lattice points inside a circle of radius 24<ref name="auto22"/>
:'''1794''' = nonagonal number,<ref name="Nonagonal number" /> number of partitions of 33 that do not contain 1 as a part<ref name="auto8"/>
:'''1795''' = number of heptagons with perimeter 38<ref>{{cite OEIS|A288253|Number of heptagons that can be formed with perimeter n}}</ref>
:'''1796''' = k such that geometric mean of phi(k) and sigma(k) is an integer<ref name="auto68"/>
:'''1797''' = number k such that phi(prime(k)) is a square<ref name="auto55"/>
:'''1798''' = 2 × 29 × 31 = 10<sub>2</sub> × 11101<sub>2</sub> × 11111<sub>2</sub>, which yield zero when the prime factors are xored together<ref>{{cite OEIS|A235488|Squarefree numbers which yield zero when their prime factors are xored together}}</ref>
:'''1799''' = 2 × 30<sup>2</sup> − 1 = a [https://oeis.org/A056220/a056220.jpg twin square]<ref name="auto83"/>

=== 1800 to 1899 ===

:'''1800''' = pentagonal pyramidal number,<ref name="Pentagonal pyramidal number" /> [[Achilles number]], also, in da Ponte's ''Don Giovanni'', the number of women Don Giovanni had slept with so far when confronted by Donna Elvira, according to Leporello's tally
:'''1801''' = [[Cuban prime|cuban prime]], sum of five and nine consecutive primes (349 + 353 + 359 + 367 + 373 and 179 + 181 + 191 + 193 + 197 + 199 + 211 + 223 + 227)<ref name="Cuban Prime" />
:'''1802''' = 2 × 30<sup>2</sup> + 2 = number of points on surface of tetrahedron with edgelength 30,<ref name="auto59"/> number of partitions of 30 such that the number of odd parts is a part<ref name="auto72"/>
:'''1803''' = number of decahexes that tile the plane isohedrally but not by translation or by 180-degree rotation (Conway criterion)<ref>{{cite OEIS|A075213|Number of polyhexes with n cells that tile the plane isohedrally but not by translation or by 180-degree rotation (Conway criterion)}}</ref>
:'''1804''' = number k such that k^64 + 1 is prime
:'''1805''' = number of squares between 43<sup>2</sup> and 43<sup>4</sup>.<ref name="auto40"/>
:'''1806''' = pronic number,<ref name="pronic number" /> product of first four terms of [[Sylvester's sequence]], [[Primary pseudoperfect number|primary pseudoperfect number]],<ref>{{Cite web|url=https://oeis.org/A054377|title=Sloane's A054377 : Primary pseudoperfect numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> only number for which ''n'' equals the denominator of the ''n''th [[Bernoulli number]],<ref>Kellner, Bernard C.; [http://www.bernoulli.org/~bk/denombneqn.pdf 'The equation denom(B<sub>''n''</sub>) = ''n'' has only one solution']</ref> [[Schröder number]]<ref>{{Cite OEIS|1=A006318|2=Large Schröder numbers|access-date=2016-05-22}}</ref>
:'''1807''' = fifth term of Sylvester's sequence<ref>{{Cite web|url=https://oeis.org/A000058|title=Sloane's A000058 : Sylvester's sequence|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
:'''1808''' = maximal number of regions the plane is divided into by drawing 43 circles<ref name="auto27"/>
:'''1809''' = sum of first 17 [[Super-prime|super-prime]]s<ref>{{cite OEIS|A083186|Sum of first n primes whose indices are primes}}</ref>
:'''1810''' = <math>\sum_{k=0}^4 \binom{4}{k}^4</math><ref>{{cite OEIS|A005260|Sum_{0..n} binomial(n,k)^4}}</ref>
:'''1811''' = Sophie Germain prime
:'''1812''' = n such that n<sup>32</sup> + 1 is prime<ref name="auto51"/>
:'''1813''' = number of polyominoes with 26 cells, symmetric about two orthogonal axes<ref>{{cite OEIS|A056877|Number of polyominoes with n cells, symmetric about two orthogonal axes}}</ref>
:'''1814''' = 1 + 6 + 36 + 216 + 1296 + 216 + 36 + 6 + 1 = sum of 4th row of triangle of powers of six<ref>{{cite OEIS|A061801|(7*6^n - 2)/5}}</ref>
:'''1815''' = polygonal chain number <math>\#(P^3_{2,1})</math><ref>{{cite OEIS|A152927|Number of sets (in the Hausdorff metric geometry) at each location between two sets defining a polygonal configuration consisting of k 4-gonal polygonal components chained with string components of length 1 as k varies}}</ref>
:'''1816''' = number of strict partions of 44<ref name="auto20"/>
:'''1817''' = total number of prime parts in all partitions of 20<ref>{{cite OEIS|A037032|Total number of prime parts in all partitions of n}}</ref>
:'''1818''' = n such that n<sup>32</sup> + 1 is prime<ref name="auto51"/>
:'''1819''' = sum of the first 32 primes, minus 32<ref>{{cite OEIS|A101301|The sum of the first n primes, minus n}}</ref>
:'''1820''' = pentagonal number,<ref name="Pentagonal number" /> pentatope number,<ref name="Pentatope number" /> number of compositions of 13 whose run-lengths are either weakly increasing or weakly decreasing<ref name="auto1">{{cite OEIS|A332835|Number of compositions of n whose run-lengths are either weakly increasing or weakly decreasing|access-date=2022-06-02}}</ref>
:'''1821''' = member of the Mian–Chowla sequence<ref name=Mian-Chowla />
:'''1822''' = number of integer partitions of 43 whose distinct parts are connected<ref name="auto86"/>
:'''1823''' = [[Super-prime|super-prime]], safe prime<ref name="Safe primes" />
:'''1824''' = 43<sup>2</sup> - 5<sup>2</sup>, the only way to express 1824 as a difference of prime squares<ref name="auto96"/>
:'''1825''' = octagonal number<ref name="auto17"/>
:'''1826''' = decagonal pyramidal number<ref name="auto62"/>
:'''1827''' = [[Vampire number|vampire number]]<ref name="Vampire number" />
:'''1828''' = meandric number, open meandric number, [[Mathematical coincidence|appears twice]] in the first 10 decimal digits of ''[[E (mathematical constant)|e]]''
:'''1829''' = composite de Polignac number<ref name="auto53"/>
:'''1830''' = triangular number
:'''1831''' = smallest prime with a gap of exactly 16 to next prime (1847)<ref>{{cite OEIS|A000230|smallest prime p such that there is a gap of exactly 2n between p and next prime, or -1 if no such prime exists}}</ref>
:'''1832''' = sum of totient function for first 77 integers
:'''1833''' = number of atoms in a decahedron with 13 shells<ref>{{cite OEIS|A004068|Number of atoms in a decahedron with n shells}}</ref>
:'''1834''' = octahedral number,<ref name="Octahedral number" /> sum of the cubes of the first five primes
:'''1835''' = absolute value of numerator of <math>D_6^{(5)}</math><ref>{{cite OEIS|A001905|From higher-order Bernoulli numbers: absolute value of numerator of D-number D2n(2n-1)}}</ref>
:'''1836''' = factor by which a [[Physics:Proton|proton]] is more massive than an [[Physics:Electron|electron]]
:'''1837''' = star number<ref name="Centered 12-gonal numbers" />
:'''1838''' = number of unimodular 2 × 2 matrices having all terms in {0,1,...,27}<ref name="auto54"/>
:'''1839''' = <math>\lfloor \sqrt[3]{13!} \rfloor </math><ref>{{cite OEIS|A214083|floor(n!^(1/3))}}</ref>
:'''1840''' = 43<sup>2</sup> - 3<sup>2</sup>, the only way to express 1840 as a difference of prime squares<ref name="auto96"/>
:'''1841''' = solution to the postage stamp problem with 3 denominations and 29 stamps,<ref>{{cite OEIS|A001208|solution to the postage stamp problem with 3 denominations and n stamps}}</ref> Mertens function zero
:'''1842''' = number of unlabeled rooted trees with 11 nodes<ref>{{cite OEIS|A000081|Number of unlabeled rooted trees with n nodes (or connected functions with a fixed point)}}</ref>
:'''1843''' = k such that phi(k) is a perfect cube,<ref>{{cite OEIS|A039771|Numbers k such that phi(k) is a perfect cube}}</ref> Mertens function zero
:'''1844''' = 3<sup>7</sup> - 7<sup>3</sup>,<ref>{{cite OEIS|A024026|3^n - n^3}}</ref> Mertens function zero
:'''1845''' = number of partitions of 25 containing at least one prime,<ref>{{cite OEIS|A235945|Number of partitions of n containing at least one prime}}</ref> Mertens function zero
:'''1846''' = sum of first 49 composite numbers<ref name="auto94"/>
:'''1847''' = [[Super-prime|super-prime]]
:'''1848''' = number of edges in the join of two cycle graphs, both of order 42<ref name="auto89"/>
:'''1849''' = 43<sup>2</sup>, palindromic in base 6 (= 12321<sub>6</sub>), centered octagonal number<ref name="Centered octagonal number" />
:'''1850''' = Number of partitions of 59 into prime parts
:'''1851''' = sum of the first 32 primes
:'''1852''' = number of quantales on 5 elements, up to isomorphism<ref>{{cite OEIS|A354493|Number of quantales on n elements, up to isomorphism}}</ref>
:'''1853''' = sum of primitive roots of 27-th prime,<ref>{{cite OEIS|A088144|Sum of primitive roots of n-th prime}}</ref> Mertens function zero
:'''1854''' = number of permutations of 7 elements with no fixed points,<ref>{{cite OEIS|A000166|Subfactorial or rencontres numbers, or derangements: number of permutations of n elements with no fixed points}}</ref> Mertens function zero
:'''1855''' = rencontres number: number of permutations of [7] with exactly one fixed point<ref>{{cite OEIS|A000240|Rencontres numbers: number of permutations of [n] with exactly one fixed point}}</ref>
:'''1856''' = sum of totient function for first 78 integers
:'''1857''' = Mertens function zero, pinwheel number<ref name="Pinwheel" />
:'''1858''' = number of 14-carbon alkanes C<sub>14</sub>H<sub>30</sub> ignoring stereoisomers<ref>{{cite OEIS|A000602|Number of n-node unrooted quartic trees; number of n-carbon alkanes C(n)H(2n+2) ignoring stereoisomers}}</ref>
:'''1859''' = composite de Polignac number<ref name="auto53"/>
:'''1860''' = number of squares in the [[Aztec diamond]] of order 30<ref>{{cite web|url=https://mathworld.wolfram.com/AztecDiamond.html|title="Aztec Diamond"|access-date=2022-09-20}}</ref>
:'''1861''' = centered square number,<ref name="Centered square numbers" /> Mertens function zero
:'''1862''' = Mertens function zero, forms a Ruth–Aaron pair with 1863 under second definition
:'''1863''' = Mertens function zero, forms a Ruth–Aaron pair with 1862 under second definition
:'''1864''' = Mertens function zero, <math>\frac{1864!-2}{2}</math> is a prime<ref>{{cite OEIS|A082671|Numbers n such that (n!-2)/2 is a prime}}</ref>
:'''1865''' = 12345<sub>6</sub>: Largest [[Senary|senary]] metadrome (number with digits in strict ascending order in base 6)<ref>{{cite OEIS|A023811|Largest metadrome (number with digits in strict ascending order) in base n}}</ref>
:'''1866''' = Mertens function zero, number of plane partitions of 16 with at most two rows<ref>{{cite OEIS|A000990|Number of plane partitions of n with at most two rows}}</ref>
:'''1867''' = prime de Polignac number<ref name="auto67"/>
:'''1868''' = smallest number of complexity 21: smallest number requiring 21 1's to build using +, * and ^<ref name="auto49"/>
:'''1869''' = Hultman number: S<sub>H</sub>(7, 4)<ref>{{cite OEIS|A164652|Hultman numbers}}</ref>
:'''1870''' = decagonal number<ref name="Decagonal" />
:'''1871''' = the first prime of the 2 consecutive twin prime pairs: (1871, 1873) and (1877, 1879)<ref>{{cite OEIS|A007530|Prime quadruples: numbers k such that k, k+2, k+6, k+8 are all prime}}</ref>
:'''1872''' = first Zagreb index of the complete graph K<sub>13</sub><ref name="auto100"/>
:'''1873''' = number of Narayana's cows and calves after 21 years<ref name="auto98"/>
:'''1874''' = area of the 25th [https://oeis.org/A080663/a080663.jpg conjoined trapezoid]<ref name="auto13"/>
:'''1875''' = 50<sup>2</sup> - 25<sup>2</sup>
:'''1876''' = number k such that k^64 + 1 is prime
:'''1877''' = number of partitions of 39 where 39 divides the product of the parts<ref>{{cite OEIS|A057568|Number of partitions of n where n divides the product of the parts}}</ref>
:'''1878''' = n such that n<sup>32</sup> + 1 is prime<ref name="auto51"/>
:'''1879''' = a prime with square index<ref>{{cite OEIS|A011757|prime(n^2)}}</ref>
:'''1880''' = the 10th element of the self convolution of Lucas numbers<ref>{{cite OEIS|A004799|Self convolution of Lucas numbers}}</ref>
:'''1881''' = [[Triaugmented triangular prism|tricapped prism]] number<ref>{{cite OEIS|A005920|Tricapped prism numbers}}</ref>
:'''1882''' = number of [[Linear separability|linearly separable]] Boolean functions in 4 variables<ref>{{cite OEIS|A000609|Number of threshold functions of n or fewer variables}}</ref>
:'''1883''' = number of conjugacy classes in the alternating group A<sub>28</sub><ref name="auto33"/>
:'''1884''' = k such that 5*2<sup>k</sup> - 1 is prime<ref name="auto69"/>
:'''1885''' = Zeisel number<ref name="Zeisel number" />
:'''1886''' = number of partitions of 6<sup>4</sup> into fourth powers<ref>{{cite OEIS|A259793|Number of partitions of n^4 into fourth powers}}</ref>
:'''1887''' = number of edges in the [[:File:Hexagonal triangle.png|hexagonal triangle]] T(34)<ref name="auto60"/>
:'''1888''' = primitive abundant number ([[Abundant number|abundant number]] all of whose proper divisors are deficient numbers)<ref name="auto92"/>
:'''1889''' = Sophie Germain prime, highly cototient number<ref name="highly cototient" />
:'''1890''' = triangular matchstick number<ref name="auto5"/>
:'''1891''' = triangular number, hexagonal number,<ref name="Hexagonal number" /> centered pentagonal number,<ref name="Centered pentagonal" /> centered triangular number<ref name="auto52"/>
:'''1892''' = pronic number<ref name="pronic number" />
:'''1893''' = 44<sup>2</sup> - 44 + 1 = H<sub>44</sub> (the 44th Hogben number)<ref name="auto77"/>
:'''1894''' = maximal number of regions the plane is divided into by drawing 44 circles<ref name="auto27"/>
:'''1895''' = Stern-Jacobsthal number<ref name="auto15"/>
:'''1896''' = member of the Mian-Chowla sequence<ref name=Mian-Chowla />
:'''1897''' = member of Padovan sequence,<ref name="Padovan sequence" /> number of triangle-free graphs on 9 vertices<ref>{{cite OEIS|A006785|Number of triangle-free graphs on n vertices}}</ref>
:'''1898''' = smallest multiple of n whose digits sum to 26<ref>{{cite OEIS|A002998|Smallest multiple of n whose digits sum to n}}</ref>
:'''1899''' = [https://oeis.org/A144391/a144391.jpg cropped hexagone]<ref name="auto44"/>

=== 1900 to 1999 ===

:'''1900''' = number of primes <= 2<sup>14</sup>.<ref name="auto3"/> Also ''1900'' (film) or ''Novecento'', 1976 movie. 1900 was the year Thorold Gosset introduced his list of [[Semiregular polytope|semiregular polytope]]s; it is also the year [[Biography:Max Brückner|Max Brückner]] published his study of polyhedral models, including [[Stellation|stellation]]s of the [[Regular icosahedron|icosahedron]], such as the novel [[Final stellation of the icosahedron|final stellation of the icosahedron]].
:'''1901''' = Sophie Germain prime, centered decagonal number
:'''1902''' = number of symmetric plane partitions of 27<ref>{{cite OEIS|A005987|Number of symmetric plane partitions of n}}</ref>
:'''1903''' = generalized catalan number<ref>{{cite OEIS|A023431|Generalized Catalan Numbers}}</ref>
:'''1904''' = number of flat partitions of 43<ref name="auto26"/>
:'''1905''' = [[Fermat pseudoprime]]<ref name="auto93"/>
:'''1906''' = number n such that 3<sup>n</sup> - 8 is prime<ref>{{cite OEIS|A217135|Numbers n such that 3^n - 8 is prime}}</ref>
:'''1907''' = safe prime,<ref name="Safe primes" /> balanced prime<ref name="Balanced prime" />
:'''1908''' = coreful perfect number<ref name="auto31"/>
:'''1909''' = [[Hyperperfect number|hyperperfect number]]<ref>{{Cite web|url=https://oeis.org/A034897|title=Sloane's A034897 : Hyperperfect numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
:'''1910''' = number of compositions of 13 having exactly one fixed point<ref>{{cite OEIS|A240736|Number of compositions of n having exactly one fixed point}}</ref>
:'''1911''' = heptagonal pyramidal number<ref name="auto82"/>
:'''1912''' = size of 6th maximum raising after one blind in pot-limit poker<ref>{{cite OEIS|A007070|4*a(n-1) - 2*a(n-2)}}</ref>
:'''1913''' = [[Super-prime|super-prime]], Honaker prime<ref name="auto39"/>
:'''1914''' = number of bipartite partitions of 12 white objects and 3 black ones<ref>{{cite OEIS|A000412|Number of bipartite partitions of n white objects and 3 black ones}}</ref>
:'''1915''' = number of nonisomorphic semigroups of order 5<ref>{{cite OEIS|A027851|Number of nonisomorphic semigroups of order n}}</ref>
:'''1916''' = sum of first 50 composite numbers<ref name="auto94"/>
:'''1917''' = number of partitions of 51 into pairwise relatively prime parts<ref name="auto71"/>
:'''1918''' = heptagonal number<ref name="heptagonal number" />
:'''1919''' = smallest number with reciprocal of period length 36 in base 10<ref>{{cite OEIS|A003060|Smallest number with reciprocal of period length n in decimal (base 10)}}</ref>
:'''1920''' = sum of the nontriangular numbers between successive triangular numbers
:'''1921''' = 4-dimensional centered cube number<ref>{{cite OEIS|A008514|4-dimensional centered cube numbers}}</ref>
:'''1922''' = Area of a square with diagonal 62<ref name="area of a square with diagonal 2n"/>
:'''1923''' = 2 × 31<sup>2</sup> + 1 = number of different 2 X 2 determinants with integer entries from 0 to 31<ref name="auto32"/>
:'''1924''' = 2 × 31<sup>2</sup> + 2 = number of points on surface of tetrahedron with edgelength 31<ref name="auto59"/>
:'''1925''' = number of ways to write 24 as an orderless product of orderless sums<ref name="auto79"/>
:'''1926''' = pentagonal number<ref name="Pentagonal number" />
:'''1927''' = 2<sup>11</sup> - 11<sup>2</sup><ref>{{cite OEIS|A024012|2^n - n^2}}</ref>
:'''1928''' = number of distinct values taken by 2^2^...^2 (with 13 2's and parentheses inserted in all possible ways)<ref>{{cite OEIS|A002845|Number of distinct values taken by 2^2^...^2 (with n 2's and parentheses inserted in all possible ways)}}</ref>
:'''1929''' = Mertens function zero, number of integer partitions of 42 whose distinct parts are connected<ref name="auto86"/>
:'''1930''' = number of pairs of consecutive integers x, x+1 such that all prime factors of both x and x+1 are at most 53<ref name="auto80"/>
:'''1931''' = Sophie Germain prime
:'''1932''' = number of partitions of 40 into prime power parts<ref name="auto87"/>
:'''1933''' = centered heptagonal number,<ref name="centered heptagonal number" /> Honaker prime<ref name="auto39"/>
:'''1934''' = sum of totient function for first 79 integers
:'''1935''' = number of edges in the join of two cycle graphs, both of order 43<ref name="auto89"/>
:'''1936''' = 44<sup>2</sup>, 18-gonal number,<ref>{{Cite web|url=https://oeis.org/A051870|title=Sloane's A051870 : 18-gonal numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> 324-gonal number.
:'''1937''' = number of chiral n-ominoes in 12-space, one cell labeled<ref>{{cite OEIS|A045648|Number of chiral n-ominoes in (n-1)-space, one cell labeled}}</ref>
:'''1938''' = Mertens function zero, number of points on surface of octahedron with edgelength 22<ref name="auto61"/>
:'''1939''' = 7-Knödel number<ref name="auto21"/>
:'''1940''' = the Mahonian number: T(8, 9)<ref name="A008302" />
:'''1941''' = maximal number of regions obtained by joining 16 points around a circle by straight lines<ref>{{cite OEIS|A000127|Maximal number of regions obtained by joining n points around a circle by straight lines. Also number of regions in 4-space formed by n-1 hyperplanes}}</ref>
:'''1942''' = number k for which 10k + 1, 10k + 3, 10k + 7, 10k + 9 and 10k + 13 are primes<ref>{{cite OEIS|A178084|Numbers k for which 10k + 1, 10k + 3, 10k + 7, 10k + 9 and 10k + 13 are primes}}</ref>
:'''1943''' = largest number not the sum of distinct tetradecagonal numbers<ref name="auto24">{{cite OEIS|A007419|Largest number not the sum of distinct n-th-order polygonal numbers}}</ref>
:'''1944''' = 3-smooth number (2<sup>3</sup>×3<sup>5</sup>), [[Achilles number]]<ref name="Achilles" />
:'''1945''' = number of partitions of 25 into relatively prime parts such that multiplicities of parts are also relatively prime<ref>{{cite OEIS|A100953|Number of partitions of n into relatively prime parts such that multiplicities of parts are also relatively prime}}</ref>
:'''1946''' = number of surface points on a cube with edge-length 19<ref name="A005897" />
:'''1947''' = k such that 5·2<sup>k</sup> + 1 is a prime factor of a Fermat number 2<sup>2<sup>m</sup></sup> + 1 for some m<ref>{{cite OEIS|A226366|Numbers k such that 5*2^k + 1 is a prime factor of a Fermat number 2^(2^m) + 1 for some m}}</ref>
:'''1948''' = number of strict solid partitions of 20<ref name="auto43"/>
:'''1949''' = smallest prime > 44<sup>2</sup>.<ref name="auto57"/>
:'''1950''' = <math>1 \cdot 2 \cdot 3 + 4 \cdot 5 \cdot 6 + 7 \cdot 8 \cdot 9 + 10 \cdot 11 \cdot 12</math>,<ref>{{cite OEIS|A319014|1*2*3 + 4*5*6 + 7*8*9 + 10*11*12 + 13*14*15 + 16*17*18 + ... + (up to n)}}</ref> largest number not the sum of distinct pentadecagonal numbers<ref name="auto24"/>
:'''1951''' = cuban prime<ref name="Cuban Prime" />
:'''1952''' = number of covers of {1, 2, 3, 4}<ref>{{cite OEIS|A055621|Number of covers of an unlabeled n-set}}</ref>
:'''1953''' = triangular number
:'''1954''' = number of sum-free subsets of {1, ..., 16}<ref name="auto41"/>
:'''1955''' = number of partitions of 25 with at least one distinct part<ref name="auto66"/>
:'''1956''' = nonagonal number<ref name="Nonagonal number" />
:'''1957''' = <math>\sum_{k=0}^{6} \frac{6!}{k!}</math> = total number of ordered k-tuples (k=0,1,2,3,4,5,6) of distinct elements from an 6-element set<ref>{{cite OEIS|A000522|Total number of ordered k-tuples of distinct elements from an n-element set}}</ref>
:'''1958''' = number of partitions of 25<ref name="auto35"/>
:'''1959''' = Heptanacci-Lucas number<ref>{{cite OEIS|A104621|Heptanacci-Lucas numbers}}</ref>
:'''1960''' = number of parts in all partitions of 33 into distinct parts<ref name="auto46"/>
:'''1961''' = number of lattice points inside a circle of radius 25<ref name="auto22"/>
:'''1962''' = number of edges in the join of the complete graph K<sub>36</sub> and the cycle graph C<sub>36</sub><ref>{{cite OEIS|A005449|Second pentagonal numbers}}</ref>
:'''1963'''! - 1 is prime<ref>{{cite OEIS|A002982|Numbers n such that n! - 1 is prime}}</ref>
:'''1964''' = number of linear forests of planted planar trees with 8 nodes<ref>{{cite OEIS|A030238|Backwards shallow diagonal sums of Catalan triangle A009766}}</ref>
:'''1965''' = total number of parts in all partitions of 17<ref name="auto16"/>
:'''1966''' = sum of totient function for first 80 integers
:'''1967''' = least edge-length of a square dissectable into at least 30 squares in the Mrs. Perkins's quilt problem<ref>{{cite OEIS|A089046|Least edge-length of a square dissectable into at least n squares in the Mrs. Perkins's quilt problem}}</ref>
:'''σ(1968)''' = σ(1967) + σ(1966)<ref>{{cite OEIS|A065900|Numbers n such that sigma(n) equals sigma(n-1) + sigma(n-2)}}</ref>
:'''1969''' = Only value less than four million for which a "mod-ification" of the standard Ackermann Function does not stabilize<ref>{{cite journal
| title=A Mod-n Ackermann Function, or What's So Special About 1969?
| url=https://archive.org/details/sim_american-mathematical-monthly_1993-02_100_2/page/180
| author=Jon Froemke
| author2=Jerrold W. Grossman
| name-list-style=amp|journal=[[The American Mathematical Monthly]]
| volume=100|issue=2|date=Feb 1993|pages= 180–183
| publisher=Mathematical Association of America
| jstor=2323780|doi=10.2307/2323780}}</ref>
:'''1970''' = number of compositions of two types of 9 having no even parts<ref>{{cite OEIS|A052542|2*a(n-1) + a(n-2)}}</ref>
:'''1971''' = <math>3^7-6^3</math><ref>{{cite OEIS|A024069|6^n - n^7}}</ref>
:'''1972''' = n such that <math>\frac{n^{37}-1}{n-1}</math> is prime<ref>{{cite OEIS|A217076|Numbers n such that (n^37-1)/(n-1) is prime}}</ref>
:{{anchor|1973}} '''1973''' = Sophie Germain prime, Leonardo prime
:'''1974''' = number of binary vectors of length 17 containing no singletons<ref name="auto50"/>
:'''1975''' = number of partitions of 28 with nonnegative rank<ref name="auto18"/>
:'''1976''' = octagonal number<ref name="auto17"/>
:'''1977''' = number of non-isomorphic multiset partitions of weight 9 with no singletons<ref>{{cite OEIS|A302545|Number of non-isomorphic multiset partitions of weight n with no singletons}}</ref>
:'''1978''' = n such that n | (3<sup>n</sup> + 5)<ref>{{cite OEIS|A277288|Positive integers n such that n divides (3^n + 5)}}</ref>
:'''1979''' = number of squares between 45<sup>2</sup> and 45<sup>4</sup>.<ref name="auto40"/>
:'''1980''' = pronic number<ref name="pronic number" />
:'''1981''' = pinwheel number<ref name="Pinwheel" />
:'''1982''' = maximal number of regions the plane is divided into by drawing 45 circles<ref name="auto27"/>
:'''1983''' = skiponacci number<ref name="auto25"/>
:'''1984''' = 11111000000 in binary, see also: 1984 (disambiguation)
:'''1985''' = [[Centered square number|centered square number]]<ref name="Centered square numbers" />
:'''1986''' = number of ways to write 25 as an orderless product of orderless sums<ref name="auto79"/>
:'''[[1987 (number)|1987]]''' = 300th [[Prime number|prime number]]
:'''1988''' = sum of the first 33 primes
:'''1989''' = number of 9-step mappings with 4 inputs<ref name="auto95"/>
:'''1990''' = Stella octangula number
:'''1991''' = 11 × 181, the 46th [[:File:1991 A187220 46.png|Gullwing]] number,<ref>{{cite OEIS|A187220|Gullwing sequence}}</ref> palindromic composite number with only palindromic prime factors<ref>{{cite OEIS|A046351|Palindromic composite numbers with only palindromic prime factors}}</ref>
:'''1992''' = number of nonisomorphic sets of nonempty subsets of a 4-set<ref>{{cite OEIS|A000612|Number of P-equivalence classes of switching functions of n or fewer variables, divided by 2}}</ref>
:'''1993''' = a number with the property that 4<sup>1993</sup> - 3<sup>1993</sup> is prime,<ref>{{oeis|A059801}}</ref> number of partitions of 30 into a prime number of parts<ref name="auto70"/>
:'''1994''' = Glaisher's function W(37)<ref>{{cite OEIS|A002470|Glaisher's function W(n)}}</ref>
:'''1995''' = number of unlabeled graphs on 9 vertices with independence number 6<ref>{{cite OEIS|A263341|Triangle read by rows: T(n,k) is the number of unlabeled graphs on n vertices with independence number k}}</ref>
:'''1996''' = a number with the property that (1996! + 3)/3 is prime<ref>{{cite OEIS|A089085|Numbers k such that (k! + 3)/3 is prime}}</ref>
:'''1997''' = <math>\sum_{k=1}^{21} {k \cdot \phi(k)}</math><ref>{{cite OEIS|A011755|Sum_{1..n} k*phi(k)}}</ref>
:'''1998''' = triangular matchstick number<ref name="auto5"/>
:'''1999''' = centered triangular number<ref>{{cite OEIS|A005448|Centered triangular numbers: 3n(n-1)/2 + 1}},</ref> number of [[Regular polygon|regular]] forms in a [[Myriagon|myriagram]].

=== Prime numbers ===

There are 135 [[Prime number|prime number]]s between 1000 and 2000:<ref>{{Cite OEIS|A038823|Number of primes between n*1000 and (n+1)*1000}}</ref><ref>{{cite web |last=Stein |first=William A. |title=The Riemann Hypothesis and The Birch and Swinnerton-Dyer Conjecture |url=https://wstein.org/talks/2017-02-10-wing-rh_and_bsd/ |website=wstein.org |date=10 February 2017 |access-date=6 February 2021}}</ref>
:1009, 1013, 1019, 1021, 1031, 1033, 1039, 1049, 1051, 1061, 1063, 1069, 1087, 1091, 1093, 1097, 1103, 1109, 1117, 1123, 1129, 1151, 1153, 1163, 1171, 1181, 1187, 1193, 1201, 1213, 1217, 1223, 1229, 1231, 1237, 1249, 1259, 1277, 1279, 1283, 1289, 1291, 1297, 1301, 1303, 1307, 1319, 1321, 1327, 1361, 1367, 1373, 1381, 1399, 1409, 1423, 1427, 1429, 1433, 1439, 1447, 1451, 1453, 1459, 1471, 1481, 1483, 1487, 1489, 1493, 1499, 1511, 1523, 1531, 1543, 1549, 1553, 1559, 1567, 1571, 1579, 1583, 1597, 1601, 1607, 1609, 1613, 1619, 1621, 1627, 1637, 1657, 1663, 1667, 1669, 1693, 1697, 1699, 1709, 1721, 1723, 1733, 1741, 1747, 1753, 1759, 1777, 1783, 1787, 1789, 1801, 1811, 1823, 1831, 1847, 1861, 1867, 1871, 1873, 1877, 1879, 1889, 1901, 1907, 1913, 1931, 1933, 1949, 1951, 1973, 1979, 1987, 1993, 1997, 1999

== Notes ==
{{Notelist}}

== References ==

{{Notelist}}
{{Reflist|30em}}

{{Large numbers}}

[[Category:1000 (number)| ]]
[[Category:Integers]]

{{Sourceattribution|1000 (number)}}