a(n) = [x^n] (1-x)^(4*n+1) * Sum_{k>=0} binomial(n+k-1,k)^4 * x^k.

A262015

a(n) = [x^n] (1-x)^(4*n+1) * Sum_{k>=0} binomial(n+k-1,k)^4 * x^k.

Terms

    a(0) =1a(1) =11a(2) =603a(3) =49682a(4) =4961755a(5) =554083761a(6) =66555527346

External references