a(n) = (3^n-1)*(3^n-3)*(3^n+3)*(3^n-4)/5!.

A275637

a(n) = (3^n-1)*(3^n-3)*(3^n+3)*(3^n-4)/5!.

Terms

    a(0) =0a(1) =0a(2) =24a(3) =3588a(4) =336336a(5) =28456296a(6) =2337415080a(7) =190203890604

External references