a(n) = n*a(n-1) + 1, a(0) = 0.

Terms

a(0) =0a(1) =1a(2) =3a(3) =10a(4) =41a(5) =206a(6) =1237a(7) =8660a(8) =69281a(9) =623530a(10) =6235301a(11) =68588312a(12) =823059745a(13) =10699776686a(14) =149796873605