a(n) = Sum_{k=0..n} binomial(4*n,k) * binomial(5*n-k-1,n-k).

A370102

a(n) = Sum_{k=0..n} binomial(4*n,k) * binomial(5*n-k-1,n-k).

Terms

    a(0) =1a(1) =8a(2) =128a(3) =2312a(4) =44032a(5) =864008a(6) =17282432a(7) =350353928a(8) =7172939776a(9) =147972367880

External references