# 800 (number)

Short description: Natural number
 ← 799 800 801 →
Cardinaleight hundred
Ordinal800th
(eight hundredth)
Factorization25 × 52
Greek numeralΩ´
Roman numeralDCCC
Binary11001000002
Ternary10021223
Quaternary302004
Quinary112005
Senary34126
Octal14408
Duodecimal56812
Vigesimal20020
Base 36M836

800 (eight hundred) is the natural number following 799 and preceding 801.

It is the sum of four consecutive primes (193 + 197 + 199 + 211). It is a Harshad number, an Achilles number and the area of a square with diagonal 40.[1]

## Integers from 801 to 899

### 800s

Main page: 801 (number)
• 801 = 32 × 89, Harshad number, number of clubs patterns appearing in 50 × 50 coins[2]
• 802 = 2 × 401, sum of eight consecutive primes (83 + 89 + 97 + 101 + 103 + 107 + 109 + 113), nontotient, happy number, sum of 4 consecutive triangular numbers[3] (171 + 190 + 210 + 231)
• 803 = 11 × 73, sum of three consecutive primes (263 + 269 + 271), sum of nine consecutive primes (71 + 73 + 79 + 83 + 89 + 97 + 101 + 103 + 107), Harshad number, number of partitions of 34 into Fibonacci parts[4]
• 804 = 22 × 3 × 67, nontotient, Harshad number, refactorable number[5]
• "The 804" is a local nickname for the Greater Richmond Region of the U.S. state of Virginia, derived from its telephone area code (although the area code covers a larger area).[citation needed]
• 805 = 5 × 7 × 23, sphenic number, number of partitions of 38 into nonprime parts[6]
• 806 = 2 × 13 × 31, sphenic number, nontotient, totient sum for first 51 integers, happy number, Phi(51)[7]
• 807 = 3 × 269, antisigma(42)[8]
• 808 = 23 × 101, refactorable number, strobogrammatic number[9]
• 809 = prime number, Sophie Germain prime,[10] Chen prime, Eisenstein prime with no imaginary part

### 810s

• 810 = 2 × 34 × 5, Harshad number, number of distinct reduced words of length 5 in the Coxeter group of "Apollonian reflections" in three dimensions,[11] number of non-equivalent ways of expressing 100,000 as the sum of two prime numbers[12]
• 811 = prime number, sum of five consecutive primes (151 + 157 + 163 + 167 + 173), Chen prime, happy number, largest minimal prime in base 9, the Mertens function of 811 returns 0
• 812 = 22 × 7 × 29, admirable number, pronic number,[13] balanced number,[14] the Mertens function of 812 returns 0
• 813 = 3 × 271, blum integer (sequence A016105 in the OEIS)
• 814 = 2 × 11 × 37, sphenic number, the Mertens function of 814 returns 0, nontotient, number of fixed hexahexes.
• 815 = 5 × 163, number of graphs with 8 vertices and a distinguished bipartite block[15]
• 816 = 24 × 3 × 17, tetrahedral number,[16] Padovan number,[17] Zuckerman number
• 817 = 19 × 43, sum of three consecutive primes (269 + 271 + 277), centered hexagonal number[18]
• 818 = 2 × 409, nontotient, strobogrammatic number[9]
• 819 = 32 × 7 × 13, square pyramidal number[19]

### 820s

• 820 = 22 × 5 × 41, triangular number, smallest triangular number that starts with the digit 8[20] Harshad number, happy number, repdigit (1111) in base 9
• 821 = prime number, twin prime, Chen prime, Eisenstein prime with no imaginary part, lazy caterer number (sequence A000124 in the OEIS), prime quadruplet with 823, 827, 829
• 822 = 2 × 3 × 137, sum of twelve consecutive primes (43 + 47 + 53 + 59 + 61 + 67 + 71 + 73 + 79 + 83 + 89 + 97), sphenic number, member of the Mian–Chowla sequence[21]
• 823 = prime number, twin prime, lucky prime, the Mertens function of 823 returns 0, prime quadruplet with 821, 827, 829
• 824 = 23 × 103, refactorable number, sum of ten consecutive primes (61 + 67 + 71 + 73 + 79 + 83 + 89 + 97 + 101 + 103), the Mertens function of 824 returns 0, nontotient
• 825 = 3 × 52 × 11, Smith number,[22] the Mertens function of 825 returns 0, Harshad number
• 826 = 2 × 7 × 59, sphenic number, number of partitions of 29 into parts each of which is used a different number of times[23]
• 827 = prime number, twin prime, part of prime quadruplet with {821, 823, 829}, sum of seven consecutive primes (103 + 107 + 109 + 113 + 127 + 131 + 137), Chen prime, Eisenstein prime with no imaginary part, strictly non-palindromic number[24]
• 828 = 22 × 32 × 23, Harshad number, triangular matchstick number[25]
• 829 = prime number, twin prime, part of prime quadruplet with {827, 823, 821}, sum of three consecutive primes (271 + 277 + 281), Chen prime, centered triangular number

### 830s

• 830 = 2 × 5 × 83, sphenic number, sum of four consecutive primes (197 + 199 + 211 + 223), nontotient, totient sum for first 52 integers
• 831 = 3 × 277, number of partitions of 32 into at most 5 parts[26]
• 832 = 26 × 13, Harshad number, member of the sequence Horadam(0, 1, 4, 2)[27]
• 833 = 72 × 17, octagonal number (sequence A000567 in the OEIS), a centered octahedral number[28]
• 834 = 2 × 3 × 139, cake number, sphenic number, sum of six consecutive primes (127 + 131 + 137 + 139 + 149 + 151), nontotient
• 835 = 5 × 167, Motzkin number[29]
Main page: 836 (number)
• 836 = 22 × 11 × 19, weird number
• 837 = 33 × 31, the 36th generalized heptagonal number[30]
• 838 = 2 × 419, palindromic number, number of distinct products ijk with 1 <= i<j<k <= 23[31]
• 839 = prime number, safe prime,[32] sum of five consecutive primes (157 + 163 + 167 + 173 + 179), Chen prime, Eisenstein prime with no imaginary part, highly cototient number[33]

### 840s

Main page: 840 (number)
• 840 = 23 × 3 × 5 × 7, highly composite number,[34] smallest number divisible by the numbers 1 to 8 (lowest common multiple of 1 to 8), sparsely totient number,[35] Harshad number in base 2 through base 10, idoneal number, balanced number,[36] sum of a twin prime (419 + 421). With 32 distinct divisors, it is the number below 1000 with the largest amount of divisors.
• 841 = 292 = 202 + 212, sum of three consecutive primes (277 + 281 + 283), sum of nine consecutive primes (73 + 79 + 83 + 89 + 97 + 101 + 103 + 107 + 109), centered square number,[37] centered heptagonal number,[38] centered octagonal number[39]
• 842 = 2 × 421, nontotient, 842!! - 1 is prime,[40] number of series-reduced trees with 18 nodes[41]
• 843 = 3 × 281, Lucas number[42]
• 844 = 22 × 211, nontotient, smallest 5 consecutive integers which are not squarefree are: 844 = 22 × 211, 845 = 5 × 132, 846 = 2 × 32 × 47, 847 = 7 × 112 and 848 = 24 × 53 [43]
• 845 = 5 × 132, concentric pentagonal number,[44] number of emergent parts in all partitions of 22 [45]
• 846 = 2 × 32 × 47, sum of eight consecutive primes (89 + 97 + 101 + 103 + 107 + 109 + 113 + 127), nontotient, Harshad number
• 847 = 7 × 112, happy number, number of partitions of 29 that do not contain 1 as a part[46]
• 848 = 24 × 53, untouchable number
• 849 = 3 × 283, the Mertens function of 849 returns 0, blum integer

### 850s

• 850 = 2 × 52 × 17, the Mertens function of 850 returns 0, nontotient, the sum of the squares of the divisors of 26 is 850 (sequence a001157 in the OEIS). The maximum possible Fair Isaac credit score, country calling code for North Korea
• 851 = 23 × 37, number of compositions of 18 into distinct parts[47]
• 852 = 22 × 3 × 71, pentagonal number,[48] Smith number[22]
• country calling code for Hong Kong
• 853 = prime number, Perrin number,[49] the Mertens function of 853 returns 0, average of first 853 prime numbers is an integer (sequence A045345 in the OEIS), strictly non-palindromic number, number of connected graphs with 7 nodes
• country calling code for Macau
• 854 = 2 × 7 × 61, sphenic number, nontotient, number of unlabeled planar trees with 11 nodes[50]
• 855 = 32 × 5 × 19, decagonal number,[51] centered cube number[52]
• country calling code for Cambodia
• 856 = 23 × 107, nonagonal number,[53] centered pentagonal number,[54] happy number, refactorable number
• country calling code for Laos
• 857 = prime number, sum of three consecutive primes (281 + 283 + 293), Chen prime, Eisenstein prime with no imaginary part
• 858 = 2 × 3 × 11 × 13, Giuga number[55]
• 859 = prime number, number of planar partitions of 11,[56] prime index prime

### 860s

• 860 = 22 × 5 × 43, sum of four consecutive primes (199 + 211 + 223 + 227), Hoax number[57]
• 861 = 3 × 7 × 41, sphenic number, triangular number,[20] hexagonal number,[58] Smith number[22]
• 862 = 2 × 431, lazy caterer number (sequence A000124 in the OEIS)
• 863 = prime number, safe prime,[32] sum of five consecutive primes (163 + 167 + 173 + 179 + 181), sum of seven consecutive primes (107 + 109 + 113 + 127 + 131 + 137 + 139), Chen prime, Eisenstein prime with no imaginary part, index of prime Lucas number[59]
• 864 = 25 × 33, Achilles number, sum of a twin prime (431 + 433), sum of six consecutive primes (131 + 137 + 139 + 149 + 151 + 157), Harshad number
• 865 = 5 × 173,
• 866 = 2 × 433, nontotient, number of one-sided noniamonds,[60] number of cubes of edge length 1 required to make a hollow cube of edge length 13
• 867 = 3 × 172, number of 5-chromatic simple graphs on 8 nodes[61]
• 868 = 22 × 7 × 31 = J3(10),[62] nontotient
• 869 = 11 × 79, the Mertens function of 869 returns 0

### 870s

• 870 = 2 × 3 × 5 × 29, sum of ten consecutive primes (67 + 71 + 73 + 79 + 83 + 89 + 97 + 101 + 103 + 107), pronic number,[13] nontotient, sparsely totient number,[35] Harshad number
• 871 = 13 × 67, thirteenth tridecagonal number
• 872 = 23 × 109, refactorable number, nontotient, 872! + 1 is prime
• 873 = 32 × 97, sum of the first six factorials from 1
• 874 = 2 × 19 × 23, sphenic number, sum of the first twenty-three primes, sum of the first seven factorials from 0, nontotient, Harshad number, happy number
• 875 = 53 × 7, unique expression as difference of positive cubes:[63] 103 - 53
• 876 = 22 × 3 × 73, generalized pentagonal number[64]
• 877 = prime number, Bell number,[65] Chen prime, the Mertens function of 877 returns 0, strictly non-palindromic number,[24] prime index prime
• 878 = 2 × 439, nontotient, number of Pythagorean triples with hypotenuse < 1000.[66]
• 879 = 3 × 293, number of regular hypergraphs spanning 4 vertices,[67] candidate Lychrel seed number

### 880s

Main page: 880 (number)
• 880 = 24 × 5 × 11 = 11!!!,[68] Harshad number; 148-gonal number; the number of n×n magic squares for n = 4.
• country calling code for Bangladesh
Main page: 881 (number)
• 881 = prime number, twin prime, sum of nine consecutive primes (79 + 83 + 89 + 97 + 101 + 103 + 107 + 109 + 113), Chen prime, Eisenstein prime with no imaginary part, happy number
• 882 = 2 × 32 × 72 = $\displaystyle{ \binom{9}{5}_2 }$ a trinomial coefficient,[69] Harshad number, totient sum for first 53 integers, area of a square with diagonal 42[1]
• 883 = prime number, twin prime, sum of three consecutive primes (283 + 293 + 307), the Mertens function of 883 returns 0
• 884 = 22 × 13 × 17, the Mertens function of 884 returns 0, number of points on surface of tetrahedron with sidelength 21[70]
• 885 = 3 × 5 × 59, sphenic number, number of series-reduced rooted trees whose leaves are integer partitions whose multiset union is an integer partition of 7.[71]
• 886 = 2 × 443, the Mertens function of 886 returns 0
• country calling code for Taiwan
• 887 = prime number followed by primal gap of 20, safe prime,[32] Chen prime, Eisenstein prime with no imaginary part
 Image:Seven-segment 8.svgImage:Seven-segment 8.svgImage:Seven-segment 8.svg
Main page: 888 (number)
• 888 = 23 × 3 × 37, sum of eight consecutive primes (97 + 101 + 103 + 107 + 109 + 113 + 127 + 131), Harshad number, strobogrammatic number,[9] happy number, 888!! - 1 is prime[72]
• 889 = 7 × 127, the Mertens function of 889 returns 0

### 890s

• 890 = 2 × 5 × 89 = 192 + 232 (sum of squares of two successive primes),[73] sphenic number, sum of four consecutive primes (211 + 223 + 227 + 229), nontotient
• 891 = 34 × 11, sum of five consecutive primes (167 + 173 + 179 + 181 + 191), octahedral number
• 892 = 22 × 223, nontotient, number of regions formed by drawing the line segments connecting any two perimeter points of a 6 times 2 grid of squares like this (sequence A331452 in the OEIS).
• 893 = 19 × 47, the Mertens function of 893 returns 0
• Considered an unlucky number in Japan , because its digits read sequentially are the literal translation of yakuza.
• 894 = 2 × 3 × 149, sphenic number, nontotient
• 895 = 5 × 179, Smith number,[22] Woodall number,[74] the Mertens function of 895 returns 0
• 896 = 27 × 7, refactorable number, sum of six consecutive primes (137 + 139 + 149 + 151 + 157 + 163), the Mertens function of 896 returns 0
• 897 = 3 × 13 × 23, sphenic number, cullen number (sequence A002064 in the OEIS)
• 898 = 2 × 449, the Mertens function of 898 returns 0, nontotient
• 899 = 29 × 31 (a twin prime product),[75] happy number, smallest number with digitsum 26,[76] number of partitions of 51 into prime parts

## References

1. Sloane, N. J. A., ed. "Sequence A001105 (a(n) = 2*n^2)". OEIS Foundation.
2. (sequence A229093 in the OEIS)
3. (sequence A005893 in the OEIS)
4. Sloane, N. J. A., ed. "Sequence A003107 (Number of partitions of n into Fibonacci parts (with a single type of 1))". OEIS Foundation. Retrieved 2022-05-25.
5. Sloane, N. J. A., ed. "Sequence A174457 (Infinitely refactorable numbers)". OEIS Foundation. Retrieved 2023-10-16.
6. Sloane, N. J. A., ed. "Sequence A002095 (Number of partitions of n into nonprime parts)". OEIS Foundation. Retrieved 2022-05-25.
7. Sloane, N. J. A., ed. "Sequence A002088 (Sum of totient function: a(n) = Sum_{k=1..n} phi(k), cf. A000010)". OEIS Foundation. Retrieved 2022-05-25.
8. Sloane, N. J. A., ed. "Sequence A024816 (Antisigma(n): Sum of the numbers less than n that do not divide n)". OEIS Foundation. Retrieved 2022-05-25.
9. Sloane, N. J. A., ed. "Sequence A000787 (Strobogrammatic numbers)". OEIS Foundation. Retrieved 2016-06-11.
10. Sloane, N. J. A., ed. "Sequence A005384 (Sophie Germain primes)". OEIS Foundation. Retrieved 2016-06-11.
11. Sloane, N. J. A., ed. "Sequence A154638 (a(n) is the number of distinct reduced words of length n in the Coxeter group of "Apollonian reflections" in three dimensions)". OEIS Foundation. Retrieved 2022-05-25.
12. Sloane, N. J. A., ed. "Sequence A065577 (Number of Goldbach partitions of 10^n)". OEIS Foundation. Retrieved 2023-08-31.
13. Sloane, N. J. A., ed. "Sequence A002378 (Oblong (or promic, pronic, or heteromecic) numbers)". OEIS Foundation. Retrieved 2016-06-11.
14. Sloane, N. J. A., ed. "Sequence A049312 (Number of graphs with a distinguished bipartite block, by number of vertices)". OEIS Foundation. Retrieved 2022-05-25.
15. Sloane, N. J. A., ed. "Sequence A000292 (Tetrahedral numbers)". OEIS Foundation. Retrieved 2016-06-11.
16. Sloane, N. J. A., ed. "Sequence A000931 (Padovan sequence)". OEIS Foundation. Retrieved 2016-06-11.
17. Sloane, N. J. A., ed. "Sequence A003215 (Hex (or centered hexagonal) numbers)". OEIS Foundation. Retrieved 2016-06-11.
18. Sloane, N. J. A., ed. "Sequence A000330 (Square pyramidal numbers)". OEIS Foundation. Retrieved 2016-06-11.
19. Sloane, N. J. A., ed. "Sequence A000217 (Triangular numbers)". OEIS Foundation. Retrieved 2016-06-11.
20. Sloane, N. J. A., ed. "Sequence A005282 (Mian-Chowla sequence)". OEIS Foundation. Retrieved 2016-06-11.
21. Sloane, N. J. A., ed. "Sequence A006753 (Smith numbers)". OEIS Foundation. Retrieved 2016-06-11.
22. Sloane, N. J. A., ed. "Sequence A098859 (Number of partitions of n into parts each of which is used a different number of times)". OEIS Foundation. Retrieved 2022-05-25.
23. Sloane, N. J. A., ed. "Sequence A016038 (Strictly non-palindromic numbers)". OEIS Foundation. Retrieved 2016-06-11.
24. (sequence A045943 in the OEIS)
25. Sloane, N. J. A., ed. "Sequence A001401 (Number of partitions of n into at most 5 parts)". OEIS Foundation. Retrieved 2022-05-25.
26. (sequence A085449 in the OEIS)
27. Sloane, N. J. A., ed. "Sequence A001845 (Centered octahedral numbers (crystal ball sequence for cubic lattice))". OEIS Foundation. Retrieved 2022-06-02.
28. Sloane, N. J. A., ed. "Sequence A001006 (Motzkin numbers)". OEIS Foundation. Retrieved 2016-06-11.
29. Sloane, N. J. A., ed. "Sequence A085787". OEIS Foundation. Retrieved 2022-05-30.
30. Sloane, N. J. A., ed. "Sequence A027430". OEIS Foundation.
31. Sloane, N. J. A., ed. "Sequence A005385 (Safe primes)". OEIS Foundation. Retrieved 2016-06-11.
32. Sloane, N. J. A., ed. "Sequence A100827 (Highly cototient numbers)". OEIS Foundation. Retrieved 2016-06-11.
33. Sloane, N. J. A., ed. "Sequence A002182 (Highly composite numbers)". OEIS Foundation. Retrieved 2016-06-11.
34. Sloane, N. J. A., ed. "Sequence A036913 (Sparsely totient numbers)". OEIS Foundation. Retrieved 2016-06-11.
35. Sloane, N. J. A., ed. "Sequence A001844 (Centered square numbers)". OEIS Foundation. Retrieved 2016-06-11.
36. Sloane, N. J. A., ed. "Sequence A069099 (Centered heptagonal numbers)". OEIS Foundation. Retrieved 2016-06-11.
37. Sloane, N. J. A., ed. "Sequence A016754 (Odd squares: a(n) = (2n+1)^2. Also centered octagonal numbers)". OEIS Foundation. Retrieved 2016-06-11.
38. Sloane, N. J. A., ed. "Sequence A007749 (Numbers k such that k!! - 1 is prime)". OEIS Foundation. Retrieved 2022-05-24.
39.
40. Sloane, N. J. A., ed. "Sequence A000032 (Lucas numbers)". OEIS Foundation. Retrieved 2016-06-11.
41. Sloane, N. J. A., ed. "Sequence A045882 (Smallest term of first run of (at least) n consecutive integers which are not squarefree)". OEIS Foundation. Retrieved 2022-05-24.
42. Sloane, N. J. A., ed. "Sequence A032527 (Concentric pentagonal numbers: floor( 5*n^2 / 4 ))". OEIS Foundation. Retrieved 2022-05-24.
43. Sloane, N. J. A., ed. "Sequence A182699 (Number of emergent parts in all partitions of n)". OEIS Foundation. Retrieved 2022-05-24.
44. Sloane, N. J. A., ed. "Sequence A002865 (Number of partitions of n that do not contain 1 as a part)". OEIS Foundation. Retrieved 2022-05-24.
45. Sloane, N. J. A., ed. "Sequence A032020 (Number of compositions (ordered partitions) of n into distinct parts)". OEIS Foundation. Retrieved 2022-05-24.
46. Sloane, N. J. A., ed. "Sequence A000326 (Pentagonal numbers)". OEIS Foundation. Retrieved 2016-06-11.
47. Sloane, N. J. A., ed. "Sequence A001608 (Perrin sequence)". OEIS Foundation. Retrieved 2016-06-11.
48. Sloane, N. J. A., ed. "Sequence A002995 (Number of unlabeled planar trees (also called plane trees) with n nodes)". OEIS Foundation. Retrieved 2022-05-24.
49. Sloane, N. J. A., ed. "Sequence A001107 (10-gonal (or decagonal) numbers)". OEIS Foundation. Retrieved 2016-06-11.
50. Sloane, N. J. A., ed. "Sequence A005898 (Centered cube numbers)". OEIS Foundation. Retrieved 2016-06-11.
51. Sloane, N. J. A., ed. "Sequence A001106 (9-gonal (or enneagonal or nonagonal) numbers)". OEIS Foundation. Retrieved 2016-06-11.
52. Sloane, N. J. A., ed. "Sequence A005891 (Centered pentagonal numbers)". OEIS Foundation. Retrieved 2016-06-11.
53. Sloane, N. J. A., ed. "Sequence A007850 (Giuga numbers)". OEIS Foundation. Retrieved 2016-06-11.
54. Sloane, N. J. A., ed. "Sequence A000219 (Number of planar partitions (or plane partitions) of n)". OEIS Foundation. Retrieved 2022-05-24.
55. Sloane, N. J. A., ed. "Sequence A019506 (Hoax numbers)". OEIS Foundation. Retrieved 2022-05-24.
56. Sloane, N. J. A., ed. "Sequence A000384 (Hexagonal numbers)". OEIS Foundation. Retrieved 2016-06-11.
57. Sloane, N. J. A., ed. "Sequence A001606 (Indices of prime Lucas numbers)". OEIS Foundation.
58. Sloane, N. J. A., ed. "Sequence A006534". OEIS Foundation. Retrieved 2022-05-10.
59. Sloane, N. J. A., ed. "Sequence A076281 (Number of 5-chromatic (i.e., chromatic number equals 5) simple graphs on n nodes)". OEIS Foundation. Retrieved 2022-05-24.
60. Sloane, N. J. A., ed. "Sequence A059376 (Jordan function J_3(n))". OEIS Foundation. Retrieved 2022-05-24.
61. Sloane, N. J. A., ed. "Sequence A014439 (Differences between two positive cubes in exactly 1 way.)". OEIS Foundation. Retrieved 2019-08-18.
62. Sloane, N. J. A., ed. "Sequence A001318 (Generalized pentagonal numbers.)". OEIS Foundation. Retrieved 2019-08-26.
63. Sloane, N. J. A., ed. "Sequence A000110 (Bell or exponential numbers)". OEIS Foundation. Retrieved 2016-06-11.
64. Sloane, N. J. A., ed. "Sequence A101929 (Number of Pythagorean triples with hypotenuse < 10^n.)". OEIS Foundation. Retrieved 2022-05-11.
65. Sloane, N. J. A., ed. "Sequence A319190 (Number of regular hypergraphs)". OEIS Foundation. Retrieved 2019-08-18.
66. Sloane, N. J. A., ed. "Sequence A007661 (Triple factorial numbers)". OEIS Foundation. Retrieved 2022-05-11.
67. Sloane, N. J. A., ed. "Sequence A111808 (Left half of trinomial triangle (A027907), triangle read by rows)". OEIS Foundation. Retrieved 2022-05-11.
68. Sloane, N. J. A., ed. "Sequence A005893 (Number of points on surface of tetrahedron)". OEIS Foundation. Retrieved 2022-05-11.
69. Sloane, N. J. A., ed. "Sequence A319312 (Number of series-reduced rooted trees whose leaves are integer partitions whose multiset union is an integer partition of n)". OEIS Foundation. Retrieved 2022-05-11.
70. Sloane, N. J. A., ed. "Sequence A007749 (Numbers k such that k!! - 1 is prime)". OEIS Foundation. Retrieved 2022-05-24.
71. Sloane, N. J. A., ed. "Sequence A069484 (a(n) = prime(n+1)^2 + prime(n)^2.)". OEIS Foundation. Retrieved 2022-05-11.
72. Sloane, N. J. A., ed. "Sequence A003261 (Woodall numbers)". OEIS Foundation. Retrieved 2016-06-11.
73. Sloane, N. J. A., ed. "Sequence A037074 (Numbers that are the product of a pair of twin primes)". OEIS Foundation. Retrieved 2022-05-11.
74. Sloane, N. J. A., ed. "Sequence A051885 (Smallest number whose sum of digits is n)". OEIS Foundation. Retrieved 2022-05-11.