cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-7 of 7 results.

A001560 Numbers with an even number of partitions.

Original entry on oeis.org

2, 8, 9, 10, 11, 15, 19, 21, 22, 25, 26, 27, 28, 30, 31, 34, 40, 42, 45, 46, 47, 50, 55, 57, 58, 59, 62, 64, 65, 66, 70, 74, 75, 78, 79, 80, 84, 86, 94, 96, 97, 98, 100, 101, 103, 106, 108, 109, 110, 112, 113, 116, 117, 120, 122, 124, 125, 126, 128, 129, 130, 131
Offset: 1

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Author

Keywords

References

  • M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 836.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Programs

  • Mathematica
    f[n_, k_] := Select[Range[250], Mod[PartitionsP[#], n] == k &]; Table[f[2, k], {k, 0, 1}] (* Clark Kimberling, Jan 05 2014 *)
  • PARI
    is(n)=numbpart(n)%2==0 \\ Charles R Greathouse IV, Apr 08 2015

A237278 Numbers k such that A000041(k) == 0 (mod 4).

Original entry on oeis.org

11, 15, 21, 26, 30, 55, 58, 59, 62, 66, 70, 74, 75, 78, 80, 84, 94, 96, 98, 100, 106, 108, 109, 112, 113, 116, 117, 120, 122, 124, 125, 126, 128, 130, 131, 133, 135, 136, 137, 141, 142, 149, 153, 154, 171, 179, 180, 187, 191, 200, 205, 206, 230, 231, 236
Offset: 1

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Author

Clark Kimberling, Feb 05 2014

Keywords

Comments

The set of positive integers is partitioned by the sequences A237278-A237281.

Examples

			A000041(11) = 56 == 0 (mod 4).
		

Crossrefs

Cf. A000041, A237276, A237279, A237280, A237281, A243935 (see crossrefs).
Cf. A121062.

Programs

  • Mathematica
    f[n_, k_] := Select[Range[250], Mod[PartitionsP[#], n] == k &]
    Table[f[4, k], {k, 0, 3}] (* A237278-A237281 *)
  • PARI
    is(n)=numbpart(n)%4==0 \\ Charles R Greathouse IV, Apr 08 2015

A083214 Numbers k for which 3 | p(k), where p(k) = A000041(k) is the k-th partition number.

Original entry on oeis.org

3, 7, 9, 10, 14, 16, 17, 20, 21, 22, 24, 26, 30, 32, 33, 35, 39, 40, 41, 43, 46, 48, 51, 52, 53, 57, 61, 63, 68, 70, 71, 75, 80, 88, 97, 102, 104, 106, 107, 111, 115, 124, 125, 129, 133, 138, 142, 147, 151, 160, 162, 163, 164, 169, 173, 178, 180, 181, 189, 191, 193
Offset: 1

Views

Author

Jon Perry, Jun 01 2003

Keywords

Examples

			A000041(7)=15=0 mod 3.
		

Crossrefs

Programs

  • Mathematica
    Select[Range[250],Mod[PartitionsP[ # ],3]==0&] (* Zak Seidov, Apr 03 2007 *)
  • PARI
    { v=[1,1,2,3,5,7,11,15,22,30,42,56,77,101,135,176,231,297,385,490,627,792,1002,1255,1575,1958,2436,3010,3718,4565,5604,6842,8349,10143,12310,14883,17977,21637,26015,31185,37338,44583,53174,63261,75175,89134]; for (i=2,length(v)-1,if (v[i]%3==0,print1(i-1","))) }
    
  • PARI
    for(n=1,300,if(polcoeff(1/eta(x)+O(x^(n+1)),n)%3==0,print1(n,","))) \\ Benoit Cloitre, Oct 06 2005
    
  • PARI
    is(n)=numbpart(n)%3==0 \\ Charles R Greathouse IV, Apr 08 2015

Formula

Conjecture : a(n) = 3n + o(n). - Benoit Cloitre, Oct 06 2005
A000041(a(n)) = A087183(n). - Zak Seidov, Apr 03 2007

Extensions

More terms from Benoit Cloitre, Oct 06 2005

A027827 Values of k for which 11 divides A000041(k).

Original entry on oeis.org

6, 8, 12, 15, 16, 17, 18, 20, 21, 25, 28, 29, 31, 32, 35, 37, 38, 39, 41, 42, 43, 49, 50, 51, 52, 54, 56, 58, 59, 61, 62, 64, 72, 74, 75, 78, 81, 82, 83, 84, 85, 87, 94, 96, 98, 104, 105, 107, 108, 109, 116, 117, 118, 119, 125, 127, 128, 129, 130, 131, 138, 140, 148
Offset: 1

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Author

Keywords

Crossrefs

Programs

  • Mathematica
    Select[Range[200], Divisible[PartitionsP[#], 11]&] (* Jean-François Alcover, Dec 12 2016 *)
  • PARI
    \ps200 for(n=0,180,if(polcoeff(1/eta(x),n,x)%11==0,print1(n,",")))
    
  • PARI
    is(n)=numbpart(n)%11==0 \\ Charles R Greathouse IV, Apr 08 2015

Extensions

More terms from Benoit Cloitre, Jun 24 2002
Offset corrected by Amiram Eldar, May 21 2022

A035700 Numbers k such that the number of partitions of k, A000041(k), is a multiple of 12.

Original entry on oeis.org

21, 26, 30, 70, 75, 80, 106, 124, 125, 133, 142, 180, 191, 200, 231, 268, 278, 297, 298, 322, 336, 339, 340, 342, 350, 351, 353, 358, 365, 374, 412, 415, 449, 465, 494, 501, 531, 548, 550, 570, 579, 580, 602, 632, 645, 648, 649, 657, 663, 674, 679, 699
Offset: 1

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Author

Keywords

Crossrefs

Cf. A000041, A035701, A243935 (see crossrefs).

Programs

A071750 Numbers k such that 13 divides p(k), the k-th partition number, A000041(k).

Original entry on oeis.org

28, 62, 84, 94, 129, 136, 173, 180, 197, 213, 219, 226, 227, 237, 240, 264, 294, 311, 318, 326, 335, 338, 357, 358, 389, 418, 453, 458, 473, 482, 484, 486, 508, 529, 538, 542, 562, 600, 635, 644, 668, 670, 684, 697, 699, 713, 714, 727, 742, 747, 751, 778
Offset: 1

Views

Author

Benoit Cloitre, Jun 24 2002

Keywords

Crossrefs

Cf. A000041, A027827, A243935 (see crossrefs).

Programs

  • Mathematica
    Select[ Range[800], Mod[ PartitionsP[ # ], 13] == 0 &]
  • PARI
    \ps800 for(n=0,600,if(polcoeff(1/eta(x),n,x)%13==0,print1(n,",")))
    
  • PARI
    is(n)=numbpart(n)%13==0 \\ Charles R Greathouse IV, Apr 08 2015

Extensions

Edited by Robert G. Wilson v, Jun 27 2002

A243936 Numbers m such that 7 divides A000041(m).

Original entry on oeis.org

5, 10, 11, 12, 16, 18, 19, 24, 26, 27, 33, 37, 39, 40, 41, 47, 48, 52, 53, 54, 55, 61, 68, 75, 76, 82, 83, 89, 96, 97, 103, 110, 111, 117, 124, 125, 131, 138, 140, 145, 147, 152, 159, 166, 170, 173, 177, 180, 187, 191, 194, 201, 208, 213, 215, 222, 225, 229, 232
Offset: 1

Views

Author

Bruno Berselli, Jun 15 2014

Keywords

Crossrefs

Numbers m such that k divides A000041(m), where k is prime: A001560 (k=2), A083214 (k=3), A243935 (k=5), this sequence (k=7), A027827 (k=11), A071750 (k=13). For k composite: A237278 (k=4), A035700 (k=12).

Programs

  • Magma
    [n: n in [1..250] | IsZero(NumberOfPartitions(n) mod 7)];
    
  • Mathematica
    Select[Range[250], Mod[PartitionsP[#], 7] == 0 &]
  • PARI
    is(n)=numbpart(n)%7==0 \\ Charles R Greathouse IV, Apr 08 2015
  • Sage
    # From Peter Luschny in A000041
    @CachedFunction
    def A000041(n):
        if n == 0: return 1
        S = 0; J = n-1; k = 2
        while 0 <= J:
            T = A000041(J)
            S = S+T if is_odd(k//2) else S-T
            J -= k if is_odd(k) else k//2
            k += 1
        return S
    [n for n in (0..250) if mod(A000041(n),7) == 0]
    
Showing 1-7 of 7 results.