a(n) = n*n! + 1 = (n+1)! - n! + 1.

Terms

a(0) =1a(1) =2a(2) =5a(3) =19a(4) =97a(5) =601a(6) =4321a(7) =35281a(8) =322561a(9) =3265921a(10) =36288001a(11) =439084801a(12) =5748019201a(13) =80951270401