a(0) = 1, a(1) = 3; for n>1, a(n) = n*a(n-1) + (-1)^n.

A110149

a(0) = 1, a(1) = 3; for n>1, a(n) = n*a(n-1) + (-1)^n.

Terms

    a(0) =1a(1) =3a(2) =7a(3) =20a(4) =81a(5) =404a(6) =2425a(7) =16974a(8) =135793a(9) =1222136a(10) =12221361a(11) =134434970a(12) =1613219641a(13) =20971855332a(14) =293605974649

External references