a(n) = (5*n)!*(4*n)! / ((3*n)!^2 * (2*n)! * n!).

A364507

a(n) = (5*n)!*(4*n)! / ((3*n)!^2 * (2*n)! * n!).

Terms

    a(0) =1a(1) =40a(2) =5880a(3) =1101100a(4) =229265400a(5) =50678855040

External references