a(n) = (7*n)!*(13*n/2)!*(n/2)! / ((3*n)!^2 * (7*n/2)!^2 * n!).

A365027

a(n) = (7*n)!*(13*n/2)!*(n/2)! / ((3*n)!^2 * (7*n/2)!^2 * n!).

Terms

    a(0) =1a(1) =1716a(2) =20612592a(3) =328206021000

External references