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.

A088220 Coefficient of x^n in g.f.^n is A000172(n).

Original entry on oeis.org

1, 2, 3, 4, 9, 24, 75, 252, 903, 3376, 13068, 51960, 211222, 874440, 3676335, 15660680, 67474980, 293617248, 1288876879, 5701688928, 25397905302, 113838544880, 513117505278, 2324638603980, 10580591966824, 48362627748240
Offset: 0

Views

Author

Michael Somos, Sep 24 2003

Keywords

Crossrefs

Cf. A242903.

Programs

  • PARI
    a(n)=polcoeff(x/serreverse(x*exp(sum(m=1, n+1, sum(k=0, m, binomial(m, k)^3)*x^m/m +x^2*O(x^n)))),n)
    for(n=0,30,print1(a(n),", ")) \\ Paul D. Hanna, May 25 2014

Formula

G.f.: x / Series_Reversion( x*exp( Sum_{n>=1} A000172(n)*x^n/n ) ), where A000172(n) is the n-th Franel number. - Paul D. Hanna, May 25 2014