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.

A376382 Expansion of e.g.f. (1/x) * Series_Reversion( x*(1 - x*(exp(x) - 1))^3 ).

Original entry on oeis.org

1, 0, 6, 9, 588, 3435, 196038, 2504271, 143382648, 3105223155, 186676465890, 5932031027703, 382522369695876, 16267245179116971, 1137287705462533758, 60811389044325205695, 4631220227358066139248, 298002734705467572715491, 24748409310987998502582138
Offset: 0

Views

Author

Seiichi Manyama, Sep 22 2024

Keywords

Crossrefs

Programs

  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(serreverse(x*(1-x*(exp(x)-1))^3)/x))
    
  • PARI
    a(n) = 3*n!*sum(k=0, n\2, (3*n+k+2)!*stirling(n-k, k, 2)/(n-k)!)/(3*n+3)!;

Formula

E.g.f. A(x) satisfies A(x) = 1/(1 - x*A(x) * (exp(x*A(x)) - 1))^3.
E.g.f.: B(x)^3, where B(x) is the e.g.f. of A371273.
a(n) = (3 * n!/(3*n+3)!) * Sum_{k=0..floor(n/2)} (3*n+k+2)! * Stirling2(n-k,k)/(n-k)!.

A376438 Expansion of e.g.f. (1/x) * Series_Reversion( x*(1 - x^2*(exp(x) - 1))^2 ).

Original entry on oeis.org

1, 0, 0, 12, 24, 40, 10860, 85764, 446992, 57788784, 1008736020, 10835748220, 965748698904, 28637803537512, 519426455756572, 37968161216666100, 1626852405783259680, 44177643556314690784, 2957776991432290423332, 163869985958022692795628, 6132727345895339422510120, 405409522521171206216078040
Offset: 0

Views

Author

Seiichi Manyama, Sep 22 2024

Keywords

Crossrefs

Programs

  • PARI
    my(N=30, x='x+O('x^N)); Vec(serlaplace(serreverse(x*(1-x^2*(exp(x)-1))^2)/x))
    
  • PARI
    a(n) = 2*n!*sum(k=0, n\3, (2*n+k+1)!*stirling(n-2*k, k, 2)/(n-2*k)!)/(2*n+2)!;

Formula

E.g.f. A(x) satisfies A(x) = 1/(1 - x^2*A(x)^2 * (exp(x*A(x)) - 1))^2.
a(n) = (2 * n!/(2*n+2)!) * Sum_{k=0..floor(n/3)} (2*n+k+1)! * Stirling2(n-2*k,k)/(n-2*k)!.
Showing 1-2 of 2 results.