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

A014180

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

Terms

    a(0) =1a(1) =5a(2) =109a(3) =3533a(4) =133501a(5) =5629505a(6) =254899765a(7) =12129399245a(8) =599084606845

External references