800 (number)

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

"Eight hundred" redirects here. For the film, see The Eight Hundred. For the year, see 800. For other uses, see 800 (disambiguation).
"811 (number)" redirects here. For the phone number, see 8-1-1. For other topics, see 811 (disambiguation).
← 799 800 801 →
Cardinaleight hundred
Ordinal800th
(eight hundredth)
Factorization25 × 52
Greek numeralΩ´
Roman numeralDCCC
Binary11001000002
Ternary10021223
Senary34126
Octal14408
Duodecimal56812
Hexadecimal32016

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 article: 801 (number)

810s

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 article: 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 article: 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

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 article: 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 article: 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 = 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
Main article: 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)". The On-Line Encyclopedia of Integer Sequences. 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))". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-25.
  5. Sloane, N. J. A. (ed.). "Sequence A174457 (Infinitely refactorable numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2023-10-16.
  6. Sloane, N. J. A. (ed.). "Sequence A002095 (Number of partitions of n into nonprime parts)". The On-Line Encyclopedia of Integer Sequences. 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)". The On-Line Encyclopedia of Integer Sequences. 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)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-25.
  9. Sloane, N. J. A. (ed.). "Sequence A000787 (Strobogrammatic numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  10. Sloane, N. J. A. (ed.). "Sequence A005384 (Sophie Germain primes)". The On-Line Encyclopedia of Integer Sequences. 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)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-25.
  12. Sloane, N. J. A. (ed.). "Sequence A065577 (Number of Goldbach partitions of 10^n)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2023-08-31.
  13. Sloane, N. J. A. (ed.). "Sequence A002378 (Oblong (or promic, pronic, or heteromecic) numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  14. Sloane, N. J. A. (ed.). "Sequence A020492 (Balanced numbers: numbers k such that phi(k) (A000010) divides sigma(k) (A000203))". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  15. Sloane, N. J. A. (ed.). "Sequence A049312 (Number of graphs with a distinguished bipartite block, by number of vertices)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-25.
  16. Sloane, N. J. A. (ed.). "Sequence A000292 (Tetrahedral numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  17. Sloane, N. J. A. (ed.). "Sequence A000931 (Padovan sequence)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  18. Sloane, N. J. A. (ed.). "Sequence A003215 (Hex (or centered hexagonal) numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  19. Sloane, N. J. A. (ed.). "Sequence A000330 (Square pyramidal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  20. Sloane, N. J. A. (ed.). "Sequence A000217 (Triangular numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  21. Sloane, N. J. A. (ed.). "Sequence A005282 (Mian-Chowla sequence)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  22. Sloane, N. J. A. (ed.). "Sequence A006753 (Smith numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  23. Sloane, N. J. A. (ed.). "Sequence A098859 (Number of partitions of n into parts each of which is used a different number of times)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-25.
  24. Sloane, N. J. A. (ed.). "Sequence A016038 (Strictly non-palindromic numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  25. (sequence A045943 in the OEIS)
  26. Sloane, N. J. A. (ed.). "Sequence A001401 (Number of partitions of n into at most 5 parts)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-25.
  27. (sequence A085449 in the OEIS)
  28. Sloane, N. J. A. (ed.). "Sequence A001845 (Centered octahedral numbers (crystal ball sequence for cubic lattice))". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-06-02.
  29. Sloane, N. J. A. (ed.). "Sequence A001006 (Motzkin numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  30. Sloane, N. J. A. (ed.). "Sequence A085787". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-30.
  31. Sloane, N. J. A. (ed.). "Sequence A027430". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  32. Sloane, N. J. A. (ed.). "Sequence A005385 (Safe primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  33. Sloane, N. J. A. (ed.). "Sequence A100827 (Highly cototient numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  34. Sloane, N. J. A. (ed.). "Sequence A002182 (Highly composite numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  35. Sloane, N. J. A. (ed.). "Sequence A036913 (Sparsely totient numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  36. Sloane, N. J. A. (ed.). "Sequence A020492 (Balanced numbers: numbers k such that phi(k) (A000010) divides sigma(k) (A000203))". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  37. Sloane, N. J. A. (ed.). "Sequence A001844 (Centered square numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  38. Sloane, N. J. A. (ed.). "Sequence A069099 (Centered heptagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  39. Sloane, N. J. A. (ed.). "Sequence A016754 (Odd squares: a(n) = (2n+1)^2. Also centered octagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  40. Sloane, N. J. A. (ed.). "Sequence A007749 (Numbers k such that k!! - 1 is prime)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-24.
  41. Sloane, N. J. A. (ed.). "Sequence A000014 (Number of series-reduced trees with n nodes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  42. Sloane, N. J. A. (ed.). "Sequence A000032 (Lucas numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  43. Sloane, N. J. A. (ed.). "Sequence A045882 (Smallest term of first run of (at least) n consecutive integers which are not squarefree)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-24.
  44. Sloane, N. J. A. (ed.). "Sequence A032527 (Concentric pentagonal numbers: floor( 5*n^2 / 4 ))". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-24.
  45. Sloane, N. J. A. (ed.). "Sequence A182699 (Number of emergent parts in all partitions of n)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-24.
  46. Sloane, N. J. A. (ed.). "Sequence A002865 (Number of partitions of n that do not contain 1 as a part)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-24.
  47. Sloane, N. J. A. (ed.). "Sequence A032020 (Number of compositions (ordered partitions) of n into distinct parts)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-24.
  48. Sloane, N. J. A. (ed.). "Sequence A000326 (Pentagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  49. Sloane, N. J. A. (ed.). "Sequence A001608 (Perrin sequence)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  50. Sloane, N. J. A. (ed.). "Sequence A002995 (Number of unlabeled planar trees (also called plane trees) with n nodes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-24.
  51. Sloane, N. J. A. (ed.). "Sequence A001107 (10-gonal (or decagonal) numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  52. Sloane, N. J. A. (ed.). "Sequence A005898 (Centered cube numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  53. Sloane, N. J. A. (ed.). "Sequence A001106 (9-gonal (or enneagonal or nonagonal) numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  54. Sloane, N. J. A. (ed.). "Sequence A005891 (Centered pentagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  55. Sloane, N. J. A. (ed.). "Sequence A007850 (Giuga numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  56. Sloane, N. J. A. (ed.). "Sequence A000219 (Number of planar partitions (or plane partitions) of n)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-24.
  57. Sloane, N. J. A. (ed.). "Sequence A019506 (Hoax numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-24.
  58. Sloane, N. J. A. (ed.). "Sequence A000384 (Hexagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  59. Sloane, N. J. A. (ed.). "Sequence A001606 (Indices of prime Lucas numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  60. Sloane, N. J. A. (ed.). "Sequence A006534". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-10.
  61. Sloane, N. J. A. (ed.). "Sequence A076281 (Number of 5-chromatic (i.e., chromatic number equals 5) simple graphs on n nodes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-24.
  62. Sloane, N. J. A. (ed.). "Sequence A059376 (Jordan function J_3(n))". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-24.
  63. Sloane, N. J. A. (ed.). "Sequence A014439 (Differences between two positive cubes in exactly 1 way.)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2019-08-18.
  64. Sloane, N. J. A. (ed.). "Sequence A001318 (Generalized pentagonal numbers.)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2019-08-26.
  65. Sloane, N. J. A. (ed.). "Sequence A000110 (Bell or exponential numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  66. Sloane, N. J. A. (ed.). "Sequence A101929 (Number of Pythagorean triples with hypotenuse < 10^n.)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-11.
  67. Sloane, N. J. A. (ed.). "Sequence A319190 (Number of regular hypergraphs)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2019-08-18.
  68. Sloane, N. J. A. (ed.). "Sequence A007661 (Triple factorial numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-11.
  69. Sloane, N. J. A. (ed.). "Sequence A111808 (Left half of trinomial triangle (A027907), triangle read by rows)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-11.
  70. Sloane, N. J. A. (ed.). "Sequence A005893 (Number of points on surface of tetrahedron)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-11.
  71. 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)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-11.
  72. Sloane, N. J. A. (ed.). "Sequence A007749 (Numbers k such that k!! - 1 is prime)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-24.
  73. Sloane, N. J. A. (ed.). "Sequence A069484 (a(n) = prime(n+1)^2 + prime(n)^2.)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-11.
  74. Sloane, N. J. A. (ed.). "Sequence A003261 (Woodall numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  75. Sloane, N. J. A. (ed.). "Sequence A037074 (Numbers that are the product of a pair of twin primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-11.
  76. Sloane, N. J. A. (ed.). "Sequence A051885 (Smallest number whose sum of digits is n)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-11.
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