a(n) = (9*n^2+3*n+1) * n!.

Terms

a(0) =1a(1) =13a(2) =86a(3) =546a(4) =3768a(5) =28920a(6) =246960a(7) =2333520a(8) =24232320a(9) =274700160a(10) =3378412800a(11) =44826566400a(12) =638509132800