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

Terms

a(0) =2a(1) =3a(2) =7a(3) =16a(4) =41a(5) =146a(6) =757a(7) =5090a(8) =40385a(9) =362962a(10) =3628901a(11) =39916922a(12) =479001745a(13) =6227020970a(14) =87178291397