a(n) = Sum_{k = 0..n} binomial(n, k)^2*binomial(n+k, k)*binomial(3*n+2*k+1, n).

A374606

a(n) = Sum_{k = 0..n} binomial(n, k)^2*binomial(n+k, k)*binomial(3*n+2*k+1, n).

Terms

    a(0) =1a(1) =16a(2) =783a(3) =52000a(4) =3984625a(5) =331782528a(6) =29167556544

External references