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

A374605

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

Terms

    a(0) =1a(1) =13a(2) =621a(3) =40864a(4) =3116125a(5) =258687513a(6) =22695228864

External references