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 1-5 of 5 results.

A218380 Number of partitions of n into distinct pentagonal parts.

Original entry on oeis.org

1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 2, 1, 0, 0, 1, 2, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 2, 1, 0, 0, 1, 2, 1, 0, 0, 0, 1, 2, 1, 0, 0, 0, 1, 2, 2, 1, 0, 1, 2, 2, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 2, 2
Offset: 0

Views

Author

Antonio Roldán, Oct 27 2012

Keywords

Examples

			A(98)=3 because 98 = 12 + 35 + 51 = 1 + 5 + 92 = 1 + 5 + 22 + 70 with 1, 5, 22, 70, 92 pentagonal numbers.
		

Crossrefs

Programs

  • PARI
    { for (n=1, 100, m=polcoeff(prod(k=1, truncate(1+sqrt(24*n+1))/6, 1+x^(k*(3*k-1)/2)), n);write("B218380.txt",n, " ",m)) }

Extensions

a(0) = 1 prepended by Seiichi Manyama, Dec 09 2017

A095699 Number of partitions of n into generalized pentagonal numbers.

Original entry on oeis.org

1, 1, 2, 2, 3, 4, 5, 7, 8, 10, 12, 14, 18, 20, 25, 29, 34, 40, 45, 53, 60, 69, 80, 89, 103, 114, 131, 147, 165, 186, 207, 232, 258, 286, 319, 352, 392, 432, 477, 525, 578, 636, 699, 765, 839, 916, 1002, 1093, 1192, 1298, 1413, 1536, 1671, 1810, 1965, 2126, 2304
Offset: 0

Views

Author

Jon Perry, Jul 06 2004

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 100; CoefficientList[Series[1/Product[(1-x^(k*(3*k-1)/2)) * (1-x^(k*(3*k+1)/2)), {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Dec 10 2017 *)
  • PARI
    b(n) = (3*n^2 + 2*n + (n%2) * (2*n + 1)) / 8; \\ A001318
    N=66; x='x+O('x^N);
    Vec(1/prod(k=1,N, (1-x^b(k))) )
    \\ Joerg Arndt, Oct 13 2014

Formula

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

A294623 Number of partitions of n into distinct generalized heptagonal numbers (A085787).

Original entry on oeis.org

1, 1, 0, 0, 1, 1, 0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 2, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 2, 2, 0, 2, 3, 1, 0, 3, 3, 1, 2, 2, 1, 1, 3, 3, 3, 2, 1, 2, 3, 4, 3, 2, 2, 3, 3, 3, 5, 3, 1, 3, 4, 3, 4, 5, 2, 3, 5, 4, 3, 4, 5, 4, 4, 3, 5, 5, 3, 5, 7, 5, 3, 6, 6, 6, 6, 5, 5, 6, 6, 5, 8, 7, 5, 5, 6, 7, 8, 8
Offset: 0

Views

Author

Ilya Gutkovskiy, Nov 05 2017

Keywords

Examples

			a(18) = 2 because we have [18] and [13, 4, 1].
		

Crossrefs

Programs

  • Mathematica
    nmax = 100; CoefficientList[Series[Product[(1 + x^(k (5 k - 3)/2)) (1 + x^(k (5 k + 3)/2)), {k, 1, nmax}], {x, 0, nmax}], x]

Formula

G.f.: Product_{k>=1} (1 + x^(k*(5*k-3)/2))*(1 + x^(k*(5*k+3)/2)).

A294624 Number of partitions of n into distinct generalized octagonal numbers (A001082).

Original entry on oeis.org

1, 1, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 2, 2, 0, 1, 1, 1, 1, 0, 2, 2, 0, 0, 1, 2, 1, 0, 1, 2, 1, 1, 2, 2, 1, 0, 2, 3, 1, 1, 2, 2, 1, 0, 1, 3, 2, 2, 3, 1, 1, 1, 3, 5, 2, 2, 3, 2, 2, 1, 3, 5, 2, 1, 3, 3, 2, 1, 3, 6, 3, 1, 3, 4, 3, 1, 4, 7, 3, 0, 3, 6, 4, 1, 2, 7, 5, 2, 4, 5, 5, 2
Offset: 0

Views

Author

Ilya Gutkovskiy, Nov 05 2017

Keywords

Examples

			a(21) = 2 because we have [21] and [16, 5].
		

Crossrefs

Programs

  • Mathematica
    nmax = 100; CoefficientList[Series[Product[(1 + x^(k (3 k - 2))) (1 + x^(k (3 k + 2))), {k, 1, nmax}], {x, 0, nmax}], x]

Formula

G.f.: Product_{k>=1} (1 + x^(k*(3*k-2)))*(1 + x^(k*(3*k+2))).

A296238 Expansion of Product_{k>0} (1 + x^(k*(3*k+1)/2)).

Original entry on oeis.org

1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 0, 2, 0, 1, 0, 0, 1, 0, 2, 0, 2, 0, 1, 0, 0, 0, 1, 1, 1, 1, 0, 1, 0, 2, 0, 2, 0, 2, 1, 1, 1, 0
Offset: 0

Views

Author

Seiichi Manyama, Dec 09 2017

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 100; CoefficientList[Series[Product[(1 + x^(k*(3*k+1)/2)), {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Dec 10 2017 *)
  • PARI
    N=66; x='x+O('x^N); Vec(prod(k=1, N, (1+x^(k*(3*k+1)/2))))
Showing 1-5 of 5 results.