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

A184423

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

Terms

    a(0) =1a(1) =12a(2) =540a(3) =33600a(4) =2425500a(5) =190702512a(6) =15849497664

External references