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.

A124461 Row 1 of rectangular table A124460; also equals the antidiagonal sums of table A124460.

Original entry on oeis.org

1, 2, 4, 9, 23, 66, 210, 731, 2744, 10959, 46058, 202028, 919386, 4321837, 20916763, 103958935, 529512396, 2759340117, 14690668955, 79813438230, 442057104246, 2493917931493, 14320972817368, 83652035642564, 496769855224824
Offset: 0

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Author

Paul D. Hanna, Nov 03 2006

Keywords

Comments

In table A124460, the o.g.f. of row n, R_n(y), satisfies: R_n(y) = Sum_{k>=0} y^k * R_k(y)^n for n>=0.

Crossrefs

Cf. A124460 (table); other rows: A124462, A124463, A124464, A124465, A124466.

Programs

  • PARI
    {a(n)=local(m=max(n,1),R=vector(m+1,r,vector(m+1,c,binomial(r+c-2,c-1)))); for(i=0,m,for(r=0,m,R[r+1]=Vec(sum(c=0,m,x^c*Ser(R[c+1])^r+O(x^(m+1))))));R[2][n+1]}

Formula

O.g.f.: A(x) = Sum_{n>=0} x^n*R_n(x) = Sum_{k>=0} x^k/(1 - x*R_k(x)), where R_n(x) is the o.g.f. of row n in table A124460.