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.

A356458 Expansion of e.g.f. ( Product_{k>0} B(x^k) )^(1/(1-x)) where B(x) = exp(exp(x)-1) = e.g.f. of Bell numbers.

Original entry on oeis.org

1, 1, 6, 38, 319, 3117, 36359, 476121, 7025708, 114118746, 2029450055, 39078892305, 810834093733, 17998186069489, 425672049713174, 10676653292086790, 283014906314277059, 7901659174554937925, 231719030698518379003, 7118469816302381503209
Offset: 0

Views

Author

Seiichi Manyama, Aug 08 2022

Keywords

Crossrefs

Programs

  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(prod(k=1, N, exp(exp(x^k)-1))^(1/(1-x))))
    
  • PARI
    a355886(n) = n!*sum(k=1, n, n\k/k!);
    a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=1, i, a355886(j)*binomial(i-1, j-1)*v[i-j+1])); v;

Formula

a(0) = 1; a(n) = Sum_{k=1..n} A355886(k) * binomial(n-1,k-1) * a(n-k).

A356460 Expansion of e.g.f. Product_{k>0} B(x^k)^k where B(x) = exp(exp(x)-1) = e.g.f. of Bell numbers.

Original entry on oeis.org

1, 1, 6, 35, 303, 2772, 32903, 410335, 6051692, 95183187, 1675869175, 31437027030, 644157830077, 13976891765137, 325719071472590, 8007861177420275, 208953947981129027, 5725964099963426924, 165258064179632753563, 4987477844227598529047
Offset: 0

Views

Author

Seiichi Manyama, Aug 08 2022

Keywords

Crossrefs

Programs

  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(prod(k=1, N, exp(exp(x^k)-1)^k)))
    
  • PARI
    a354863(n) = n!*sumdiv(n, d, n/d/d!);
    a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=1, i, a354863(j)*binomial(i-1, j-1)*v[i-j+1])); v;

Formula

E.g.f.: Product_{k>0} exp(k * (exp(x^k)-1)).
a(0) = 1; a(n) = Sum_{k=1..n} A354863(k) * binomial(n-1,k-1) * a(n-k).
Showing 1-2 of 2 results.