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.

A322802 Number of compositions (ordered partitions) of n into centered hexagonal numbers (A003215).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 7, 8, 10, 13, 17, 22, 28, 36, 45, 56, 70, 88, 111, 140, 178, 226, 286, 361, 455, 573, 721, 909, 1148, 1451, 1834, 2318, 2928, 3695, 4661, 5880, 7420, 9366, 11826, 14935, 18860, 23812, 30059, 37941, 47888, 60445, 76302, 96327
Offset: 0

Views

Author

Ilya Gutkovskiy, Dec 26 2018

Keywords

Crossrefs

Programs

  • Maple
    h:= proc(n) option remember; `if`(n<0, 0, (t->
          `if`(3*t*(t+1)+1>n, t-1, t))(1+h(n-1)))
        end:
    a:= proc(n) option remember; `if`(n=0, 1,
          add(a(n-(3*i*(i+1)+1)), i=0..h(n)))
        end:
    seq(a(n), n=0..60);  # Alois P. Heinz, Dec 28 2018
  • Mathematica
    nmax = 53; CoefficientList[Series[1/(1 - Sum[x^(3 k (k + 1) + 1), {k, 0, nmax}]), {x, 0, nmax}], x]

Formula

G.f.: 1/(1 - Sum_{k>=0} x^(3*k*(k+1)+1)).

A322803 Number of compositions (ordered partitions) of n into centered heptagonal numbers (A069099).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 14, 18, 23, 29, 36, 45, 55, 67, 82, 101, 125, 155, 192, 239, 297, 368, 455, 562, 694, 857, 1058, 1308, 1619, 2005, 2483, 3074, 3805, 4708, 5822, 7198, 8900, 11007, 13616, 16846, 20845, 25795, 31918, 39489
Offset: 0

Views

Author

Ilya Gutkovskiy, Dec 26 2018

Keywords

Crossrefs

Programs

  • Maple
    h:= proc(n) option remember; `if`(n<1, 0, (t->
          `if`((7*(t-1)*t+2)/2>n, t-1, t))(1+h(n-1)))
        end:
    a:= proc(n) option remember; `if`(n=0, 1,
          add(a(n-(7*(i-1)*i+2)/2), i=1..h(n)))
        end:
    seq(a(n), n=0..60);  # Alois P. Heinz, Dec 28 2018
  • Mathematica
    nmax = 54; CoefficientList[Series[1/(1 - Sum[x^(7 k (k + 1)/2 + 1), {k, 0, nmax}]), {x, 0, nmax}], x]

Formula

G.f.: 1/(1 - Sum_{k>=0} x^(7*k*(k+1)/2+1)).

A322853 Number of compositions (ordered partitions) of n into pentagonal pyramidal numbers (A002411).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 7, 9, 12, 16, 21, 27, 34, 44, 57, 74, 96, 124, 159, 205, 265, 343, 444, 574, 740, 954, 1231, 1590, 2055, 2656, 3430, 4428, 5716, 7380, 9531, 12312, 15902, 20536, 26518, 34242, 44218, 57106, 73751, 95245, 122999, 158837, 205117
Offset: 0

Views

Author

Ilya Gutkovskiy, Dec 29 2018

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 51; CoefficientList[Series[1/(1 - Sum[x^(k^2 (k + 1)/2), {k, 1, nmax}]), {x, 0, nmax}], x]

Formula

G.f.: 1/(1 - Sum_{k>=1} x^(k^2*(k+1)/2)).
Showing 1-3 of 3 results.