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

A103870

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

Terms

    a(0) =1a(1) =4a(2) =44a(3) =580a(4) =8428a(5) =129504a(6) =2063996a(7) =33752576a(8) =562597100a(9) =9516705808a(10) =162878088544

External references