a(n) = n!*(3*n^2 - 15*n + 10)/6.

A034861

a(n) = n!*(3*n^2 - 15*n + 10)/6.

Terms

    a(0) =-8a(1) =200a(2) =3360a(3) =43680a(4) =551040a(5) =7136640a(6) =96768000a(7) =1383782400a(8) =20916403200a(9) =334183449600

External references