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.

A355470 Expansion of Sum_{k>=0} (k^3 * x)^k/(1 - k^3 * x)^(k+1).

Original entry on oeis.org

1, 1, 66, 21222, 18927560, 36030104000, 125486684755152, 722272396672485568, 6391048590559497227904, 82362961035803105954736768, 1482370265813455598541301007360, 36031982428595760278113744699088384, 1150873035676373345725887922070318410752
Offset: 0

Views

Author

Seiichi Manyama, Jul 03 2022

Keywords

Crossrefs

Programs

  • PARI
    my(N=20, x='x+O('x^N)); Vec(sum(k=0, N, (k^3*x)^k/(1-k^3*x)^(k+1)))
    
  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(1+sum(k=1, N, exp(k^3*x)*(k^3*x)^k/k!)))
    
  • PARI
    a(n) = sum(k=0, n, k^(3*n)*binomial(n, k));

Formula

E.g.f.: Sum_{k>=0} exp(k^3 * x) * (k^3 * x)^k/k!.
a(n) = Sum_{k=0..n} k^(3*n) * binomial(n,k).

A355465 Expansion of Sum_{k>=0} (k^k * x/(1 - k^k * x))^k.

Original entry on oeis.org

1, 1, 17, 19812, 4296562388, 298027622009561768, 10314429455106223377205859112, 256923580408437742134605162130019436138968, 6277101736867794060924264576844540796924098543875220742528
Offset: 0

Views

Author

Seiichi Manyama, Jul 03 2022

Keywords

Crossrefs

Programs

  • PARI
    my(N=10, x='x+O('x^N)); Vec(sum(k=0, N, (k^k*x/(1-k^k*x))^k))
    
  • PARI
    a(n) = if(n==0, 1, sum(k=1, n, k^(k*n)*binomial(n-1, k-1)));

Formula

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