a(n) = n!*(4*n^3 - 30*n^2 + 40*n + 3)/24.

A034863

a(n) = n!*(4*n^3 - 30*n^2 + 40*n + 3)/24.

Terms

    a(0) =-61a(1) =-235a(2) =810a(3) =38850a(4) =757680a(5) =12836880a(6) =212133600a(7) =3554258400a(8) =61372080000

External references