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 1-2 of 2 results.

A380208 Expansion of e.g.f. exp( (1+3*x)^(1/3) - 1 ).

Original entry on oeis.org

1, 1, -1, 5, -39, 421, -5809, 97609, -1933455, 44107881, -1138752449, 32820576141, -1044523471991, 36379398867085, -1376300966184689, 56200996031812241, -2463713702730471199, 115400572452587463249, -5751849729149085927425, 303954806150664749166101
Offset: 0

Views

Author

Seiichi Manyama, Jan 16 2025

Keywords

Crossrefs

Programs

  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(exp((1+3*x)^(1/3)-1)))

Formula

a(n) = Sum_{k=0..n} 3^(n-k) * Stirling1(n,k) * Bell(k).
a(n) = (1/e) * 3^n * n! * Sum_{k>=0} binomial(k/3,n)/k!.
a(0) = 1; a(n) = Sum_{k=1..n} (Product_{j=0..k-1} (-3*j+1)) * binomial(n-1,k-1) * a(n-k).

A380228 Expansion of e.g.f. exp( exp( (exp(2*x)-1)/2 ) - 1 ).

Original entry on oeis.org

1, 1, 4, 21, 139, 1108, 10287, 108699, 1285228, 16783395, 239571125, 3706900992, 61746357449, 1100827515921, 20902202270580, 420903243601485, 8955301860908499, 200664408693149164, 4721693823656357303, 116370390417335016731, 2997078741899026174972, 80492590654279893652283
Offset: 0

Views

Author

Seiichi Manyama, Jan 17 2025

Keywords

Crossrefs

Programs

  • PARI
    my(N=30, x='x+O('x^N)); Vec(serlaplace(exp(exp((exp(2*x)-1)/2)-1)))

Formula

a(n) = Sum_{k=0..n} 2^(n-k) * Stirling2(n,k) * Bell(k).
Showing 1-2 of 2 results.