A228906 A diagonal of triangle A228904.

1, 2, 7, 62, 1031, 24782, 774180, 29763855, 1359654560, 71984907423, 4335406418694, 292753300447894, 21909289407621069, 1800106653483146619, 161097567109713138999, 15599377878403186676330, 1625083531855929644443019, 181238001661004834528467994, 21545324993880123460418461719

Offset

1,2

Comments

Triangle A228904 is defined by g.f.: exp( Sum_{n>=1} x^n/n * Sum_{k=0..n} binomial(n*k, k^2) * y^k ).

Links

Table of n, a(n) for n=1..19.

Prog

 (PARI) {a(n)=polcoeff(polcoeff(exp(sum(m=1, n, x^m/m*sum(j=0, m, binomial(m*j, j^2)*y^j))+x*O(x^n)), n, x), n-1, y)}
for(n=1, 20, print1(a(n), ", "))

Crossrefs

Cf. A228904.

Sequence in context: A132524 A153694 A354306 * A100523 A181030 A006506

Adjacent sequences: A228903 A228904 A228905 * A228907 A228908 A228909

Keyword

nonn

Author

Paul D. Hanna, Sep 07 2013

Status

approved