a(n) = n*a(n-1) - 1 with a(1)=1.

Terms

a(0) =1a(1) =1a(2) =2a(3) =7a(4) =34a(5) =203a(6) =1420a(7) =11359a(8) =102230a(9) =1022299a(10) =11245288a(11) =134943455a(12) =1754264914a(13) =24559708795a(14) =368395631924