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 1-4 of 4 results.

A375661 Expansion of e.g.f. 1 / (1 - x * (exp(x) - 1))^3.

Original entry on oeis.org

1, 0, 6, 9, 156, 735, 9738, 83181, 1129656, 13662459, 207281190, 3151269033, 54457383060, 980680471095, 19240001086530, 397345461622245, 8763618490102128, 203472380293912563, 4991552271140255838, 128517790560854181537, 3472936316648987980620
Offset: 0

Views

Author

Seiichi Manyama, Aug 23 2024

Keywords

Crossrefs

Programs

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

Formula

E.g.f.: B(x)^3, where B(x) is the e.g.f. of A052848.
a(n) = (n!/2) * Sum_{k=0..floor(n/2)} (k+2)! * Stirling2(n-k,k)/(n-k)!.

A375671 Expansion of e.g.f. 1 / (1 + x * log(1 - x))^2.

Original entry on oeis.org

1, 0, 4, 6, 88, 420, 5148, 44520, 587424, 7203168, 109106640, 1689621120, 29620245312, 546547098240, 10989238893696, 233884517368320, 5324618721070080, 128058198711690240, 3260308438558826496, 87336328336058603520, 2459915920512955929600
Offset: 0

Views

Author

Seiichi Manyama, Aug 23 2024

Keywords

Crossrefs

Programs

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

Formula

E.g.f.: B(x)^2, where B(x) is the e.g.f. of A052830.
a(n) = n! * Sum_{k=0..floor(n/2)} (k+1)! * |Stirling1(n-k,k)|/(n-k)!.

A376381 Expansion of e.g.f. (1/x) * Series_Reversion( x*(1 - x*(exp(x) - 1))^2 ).

Original entry on oeis.org

1, 0, 4, 6, 272, 1570, 63912, 792554, 33262784, 684763650, 30981768680, 915838324522, 45524048263872, 1765020653500130, 97096528136899592, 4651295721203951850, 283478019364268181632, 16107548441248677913858, 1084981357752210351649512, 71056829948555342150405354, 5267564532376249471978526720
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*(exp(x)-1))^2)/x))
    
  • PARI
    a(n) = 2*n!*sum(k=0, n\2, (2*n+k+1)!*stirling(n-k, k, 2)/(n-k)!)/(2*n+2)!;

Formula

E.g.f. A(x) satisfies A(x) = 1/(1 - x*A(x) * (exp(x*A(x)) - 1))^2.
E.g.f.: B(x)^2, where B(x) is the e.g.f. of A371271.
a(n) = (2 * n!/(2*n+2)!) * Sum_{k=0..floor(n/2)} (2*n+k+1)! * Stirling2(n-k,k)/(n-k)!.

A377646 Expansion of e.g.f. (1 + x * (exp(x) - 1))^2.

Original entry on oeis.org

1, 0, 4, 6, 32, 130, 432, 1274, 3488, 9090, 22880, 56122, 134928, 319202, 745136, 1719930, 3931712, 8912386, 20053440, 44825978, 99614000, 220200162, 484441232, 1061157946, 2315254752, 5033163650, 10905189152, 23555209914, 50734299728, 108984793570
Offset: 0

Views

Author

Seiichi Manyama, Nov 04 2024

Keywords

Crossrefs

Programs

  • PARI
    a(n) = n!*sum(k=0, n\2, k!*binomial(2, k)*stirling(n-k, k, 2)/(n-k)!);

Formula

a(n) = n! * Sum_{k=0..floor(n/2)} k! * binomial(2,k) * Stirling2(n-k,k)/(n-k)!.
Showing 1-4 of 4 results.