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

Terms

a(0) =1a(1) =3a(2) =8a(3) =27a(4) =124a(5) =725a(6) =5046a(7) =40327a(8) =362888a(9) =3628809a(10) =39916810a(11) =479001611a(12) =6227020812a(13) =87178291213