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.

A329096 Row sums of A329057.

Original entry on oeis.org

1, 2, 8, 47, 374, 3852, 49398, 762785, 13805702, 286796072, 6727496456, 175903776622, 5073226515772, 160000741383368, 5478160073933490, 202366832844684645, 8022796547785815878, 339769654607776375824, 15309183806159727889536, 731253261602981693567090, 36909816019024064633444820
Offset: 0

Views

Author

Stefano Spezia, Nov 04 2019

Keywords

Crossrefs

Programs

  • Mathematica
    Table[(Binomial[2n,n]Hypergeometric2F1[1,-n,-2n,1+n])/(1+n),{n,0,20}]
  • PARI
    {a(n) = sum(k=0,n, binomial(2*n-k, n) * (n+1)^(k-1) )}
    for(n=0,25,print1(a(n),", ")) \\ Paul D. Hanna, Sep 12 2024
    
  • PARI
    {a(n) = my(C = (1 - sqrt(1-4*x +x^2*O(x^n)))/2);
    (1/(n+1)) * polcoef( C'/(1 - (n+1)*C), n)}
    for(n=0,25,print1(a(n),", ")) \\ Paul D. Hanna, Sep 12 2024

Formula

a(n) = binomial(2*n, n)*2F1([1, -n], [-2*n], 1 + n)/(1 + n), where 2F1 is the hypergeometric function.
a(n) ~ exp(2) * n^(n-1). - Vaclav Kotesovec, Nov 04 2019
From Paul D. Hanna, Sep 12 2024: (Start)
a(n) = Sum_{k=0..n} binomial(2*n-k, n) * (n+1)^(k-1).
a(n) = (1/(n+1)) * [x^n] C(x)'/(1 - (n+1)*C(x)) for n >= 0 where C(x) = (1 - sqrt(1-4*x))/2 is the g.f. of the Catalan numbers (A000108). (End)