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.

A371370 E.g.f. satisfies A(x) = -log(1 - x/(1 - A(x))^2).

Original entry on oeis.org

0, 1, 5, 62, 1246, 34734, 1239708, 53958456, 2771832656, 164151829440, 11010949643640, 825134834757936, 68321156113803360, 6194283782068848816, 610322188305019432032, 64936303681095948453120, 7419917758371561069774336, 906217650382400588573066880
Offset: 0

Views

Author

Seiichi Manyama, Mar 20 2024

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Sum[(2*n+k-2)!/(2*n-1)! * Abs[StirlingS1[n,k]], {k,1,n}], {n,0,20}] (* Vaclav Kotesovec, Sep 10 2024 *)
  • PARI
    my(N=20, x='x+O('x^N)); concat(0, Vec(serlaplace(serreverse((1-x)^2*(1-exp(-x))))))
    
  • PARI
    a(n) = sum(k=1, n, (2*n+k-2)!/(2*n-1)!*abs(stirling(n, k, 1)));

Formula

E.g.f.: Series_Reversion( (1 - x)^2 * (1 - exp(-x)) ).
a(n) = Sum_{k=1..n} (2*n+k-2)!/(2*n-1)! * |Stirling1(n,k)|.
a(n) ~ LambertW(2*exp(3))^n * n^(n-1) / (sqrt(2*(1 + LambertW(2*exp(3)))) * (LambertW(2*exp(3)) - 2)^(3*n-1) * exp(n)). - Vaclav Kotesovec, Sep 10 2024

A376037 E.g.f. satisfies A(x) = (exp(x / (1 - A(x))^2) - 1) / (1 - A(x)).

Original entry on oeis.org

0, 1, 7, 115, 3047, 111771, 5244555, 299941195, 20239069807, 1574068019851, 138641219870243, 13640672949173403, 1482772864485867399, 176478769995088245595, 22825571074271407363771, 3187825736999237502879019, 478120273969744650293424095
Offset: 0

Views

Author

Seiichi Manyama, Sep 07 2024

Keywords

Crossrefs

Programs

  • PARI
    a(n) = sum(k=1, n, (2*n+2*k-2)!/(2*n+k-1)!*stirling(n, k, 2));

Formula

a(n) = Sum_{k=1..n} (2*n+2*k-2)!/(2*n+k-1)! * Stirling2(n,k).
E.g.f.: Series_Reversion( (1 - x)^2 * log(1 + x * (1 - x)) ).

A368033 E.g.f. satisfies A(x) = log(1 + x/(1 - A(x))^2).

Original entry on oeis.org

0, 1, 3, 26, 370, 7334, 186468, 5787144, 212100208, 8964974016, 429304991880, 22971063265776, 1358260804832160, 87949592273821680, 6189420503357272608, 470384337802047909120, 38393707193347187344896, 3349704214386311986028160
Offset: 0

Views

Author

Seiichi Manyama, Mar 20 2024

Keywords

Crossrefs

Programs

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

Formula

E.g.f.: Series_Reversion( (1 - x)^2 * (exp(x) - 1) ).
a(n) = Sum_{k=1..n} (2*n+k-2)!/(2*n-1)! * Stirling1(n,k).
a(n) ~ LambertW(2*exp(1))^n * n^(n-1) / (sqrt(2*(1 + LambertW(2*exp(1)))) * exp(n) * (2 - LambertW(2*exp(1)))^(3*n - 1)). - Vaclav Kotesovec, Mar 29 2024

A376035 E.g.f. satisfies A(x) = exp(x / (1 - A(x))^3) - 1.

Original entry on oeis.org

0, 1, 7, 118, 3205, 120466, 5790619, 339216046, 23443311049, 1867308836986, 168435092561671, 16971155810393302, 1889194092179682061, 230257485553145337106, 30496977601634473249363, 4361533380688447142658046, 669865656003334085318195089
Offset: 0

Views

Author

Seiichi Manyama, Sep 07 2024

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Sum[(3*n+k-2)!/(3*n-1)! * StirlingS2[n,k], {k,1,n}], {n,0,20}] (* Vaclav Kotesovec, Sep 10 2024 *)
  • PARI
    my(N=20, x='x+O('x^N)); concat(0, Vec(serlaplace(serreverse((1-x)^3*log(1+x)))))
    
  • PARI
    a(n) = sum(k=1, n, (3*n+k-2)!/(3*n-1)!*stirling(n, k, 2));

Formula

E.g.f.: Series_Reversion( (1 - x)^3 * log(1+x) ).
a(n) = Sum_{k=1..n} (3*n+k-2)!/(3*n-1)! * Stirling2(n,k).
a(n) ~ 3^(4*n-2) * LambertW(2*exp(1/3)/3)^(3*n-1) * n^(n-1) / (sqrt(1 + LambertW(2*exp(1/3)/3)) * exp(n) * 2^(3*n-1) * (3*LambertW(2*exp(1/3)/3) - 1)^(4*n-1)). - Vaclav Kotesovec, Sep 10 2024
Showing 1-4 of 4 results.