a(n) = (9*n)!*(4*n)!/((8*n)!*(3*n)!*(2*n)!).

A295439

a(n) = (9*n)!*(4*n)!/((8*n)!*(3*n)!*(2*n)!).

Terms

    a(0) =1a(1) =18a(2) =714a(3) =32175a(4) =1531530a(5) =75167268a(6) =3762157035a(7) =190878381495

External references