G.f.: 1 = Sum_{n>=0} a(n)*x^n * [ Sum_{k=0..n+1} binomial(n+1, k)^2*(-x)^k ]^3.

A247030

G.f.: 1 = Sum_{n>=0} a(n)*x^n * [ Sum_{k=0..n+1} binomial(n+1, k)^2*(-x)^k ]^3.

Terms

    a(0) =1a(1) =3a(2) =33a(3) =739a(4) =26826a(5) =1404627a(6) =98887630a(7) =8932402203

External references