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

Terms

a(0) =1a(1) =2a(2) =10a(3) =60a(4) =408a(5) =3120a(6) =26640a(7) =252000a(8) =2620800a(9) =29756160a(10) =366508800a(11) =4869849600a(12) =69455232000