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.

A375660 Expansion of e.g.f. 1 / (1 - x * (exp(x) - 1))^2.

Original entry on oeis.org

1, 0, 4, 6, 80, 370, 4152, 34034, 413632, 4744674, 66354680, 954512482, 15454225536, 263909265074, 4898255210968, 96284064551250, 2022022344889472, 44858682139345090, 1052826609589372152, 25994393541984673154, 674563101823606851520, 18337775305498096349202
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))^2))
    
  • PARI
    a(n) = n!*sum(k=0, n\2, (k+1)!*stirling(n-k, k, 2)/(n-k)!);

Formula

E.g.f.: B(x)^2, where B(x) is the e.g.f. of A052848.
a(n) = n! * Sum_{k=0..floor(n/2)} (k+1)! * Stirling2(n-k,k)/(n-k)!.

A375672 Expansion of e.g.f. 1 / (1 + x * log(1 - x))^3.

Original entry on oeis.org

1, 0, 6, 9, 168, 810, 11592, 103320, 1511808, 19350576, 315908640, 5127930720, 95386497984, 1843728194880, 38978317929600, 866801578406400, 20627303078937600, 516780346452733440, 13695223899883530240, 381043219813390540800, 11135125489382277811200
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))^3))
    
  • PARI
    a(n) = n!*sum(k=0, n\2, (k+2)!*abs(stirling(n-k, k, 1))/(n-k)!)/2;

Formula

E.g.f.: B(x)^3, where B(x) is the e.g.f. of A052830.
a(n) = (n!/2) * Sum_{k=0..floor(n/2)} (k+2)! * |Stirling1(n-k,k)|/(n-k)!.

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)!.

A377680 Expansion of e.g.f. (1 + x * (exp(x) - 1))^3.

Original entry on oeis.org

1, 0, 6, 9, 84, 375, 1998, 11361, 60840, 299403, 1368930, 5906373, 24362748, 97019247, 375712470, 1422455625, 5286155088, 19340722707, 69831127242, 249265052301, 880927979940, 3086000399223, 10726216043070, 37020328044945, 126961071656184, 432900077950875
Offset: 0

Views

Author

Seiichi Manyama, Nov 04 2024

Keywords

Crossrefs

Programs

  • PARI
    a(n) = n!*sum(k=0, n\2, k!*binomial(3, k)*stirling(n-k, k, 2)/(n-k)!);

Formula

a(n) = n! * Sum_{k=0..floor(n/2)} k! * binomial(3,k) * Stirling2(n-k,k)/(n-k)!.
Showing 1-4 of 4 results.