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 1-3 of 3 results.

A373012 Number of distinct partitions p of n such that max(p) == 1 mod 3.

Original entry on oeis.org

0, 1, 0, 0, 1, 1, 1, 3, 2, 2, 4, 3, 4, 7, 7, 8, 12, 13, 15, 20, 21, 24, 31, 34, 39, 49, 54, 62, 76, 84, 97, 116, 130, 148, 174, 195, 221, 257, 287, 325, 374, 419, 472, 540, 604, 679, 772, 861, 966, 1092, 1218, 1362, 1533, 1706, 1903, 2133, 2368, 2635, 2943, 3263, 3622, 4033, 4463
Offset: 0

Views

Author

Seiichi Manyama, May 20 2024

Keywords

Examples

			a(7) = 3 counts these partitions: 7, 43, 421.
		

Crossrefs

Programs

  • PARI
    my(N=70, x='x+O('x^N)); concat(0, Vec(sum(k=0, N, x^(3*k+1)*prod(j=1, 3*k, 1+x^j))))

Formula

G.f.: Sum_{k>=0} x^(3*k+1) * Product_{j=1..3*k} (1+x^j).
A000009(n) = A372893(n) + a(n) + A373013(n).

A373013 Number of distinct partitions p of n such that max(p) == 2 mod 3.

Original entry on oeis.org

0, 0, 1, 1, 0, 1, 1, 1, 3, 3, 3, 5, 5, 5, 8, 9, 9, 13, 15, 17, 23, 26, 29, 36, 41, 46, 57, 64, 72, 87, 98, 111, 131, 149, 168, 197, 223, 251, 291, 328, 369, 423, 476, 534, 609, 683, 765, 867, 970, 1084, 1222, 1365, 1522, 1710, 1905, 2121, 2374, 2639, 2931, 3269, 3627, 4020, 4471, 4950
Offset: 0

Views

Author

Seiichi Manyama, May 20 2024

Keywords

Examples

			a(8) = 3 counts these partitions: 8, 53, 521.
		

Crossrefs

Programs

  • PARI
    my(N=70, x='x+O('x^N)); concat([0, 0], Vec(sum(k=0, N, x^(3*k+2)*prod(j=1, 3*k+1, 1+x^j))))

Formula

G.f.: Sum_{k>=0} x^(3*k+2) * Product_{j=1..3*k+1} (1+x^j).
A000009(n) = A372893(n) + A373012(n) + a(n).

A373029 Triangle T(n,k), n >= 0, 0 <= k <= n, read by rows, where T(n,k) is the number of distinct partitions p of n such that max(p) is a multiple of k.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 0, 2, 1, 1, 0, 2, 1, 1, 1, 0, 3, 1, 1, 1, 1, 0, 4, 2, 2, 1, 1, 1, 0, 5, 3, 1, 2, 1, 1, 1, 0, 6, 3, 1, 2, 2, 1, 1, 1, 0, 8, 4, 3, 2, 2, 2, 1, 1, 1, 0, 10, 5, 3, 2, 3, 2, 2, 1, 1, 1, 0, 12, 6, 4, 2, 3, 3, 2, 2, 1, 1, 1, 0, 15, 7, 6, 3, 3, 4, 3, 2, 2, 1, 1, 1, 0, 18, 9, 6, 4, 3, 4, 4, 3, 2, 2, 1, 1, 1
Offset: 0

Views

Author

Seiichi Manyama, May 20 2024

Keywords

Examples

			Triangle begins:
  1;
  0,  1;
  0,  1, 1;
  0,  2, 1, 1;
  0,  2, 1, 1, 1;
  0,  3, 1, 1, 1, 1;
  0,  4, 2, 2, 1, 1, 1;
  0,  5, 3, 1, 2, 1, 1, 1;
  0,  6, 3, 1, 2, 2, 1, 1, 1;
  0,  8, 4, 3, 2, 2, 2, 1, 1, 1;
  0, 10, 5, 3, 2, 3, 2, 2, 1, 1, 1;
  0, 12, 6, 4, 2, 3, 3, 2, 2, 1, 1, 1;
  0, 15, 7, 6, 3, 3, 4, 3, 2, 2, 1, 1, 1;
  0, 18, 9, 6, 4, 3, 4, 4, 3, 2, 2, 1, 1, 1;
		

Crossrefs

Row sums give A373030.
Column k=0..3 give A000007, A000009, A026838, A372893.
T(2n,n) gives A000009.
Cf. A363048.

Formula

For k > 0, g.f. of column k: Sum_{i>=0} x^(k*i) * Product_{j=1..k*i-1} (1+x^j).
Showing 1-3 of 3 results.