a(n) = n! - 2(n-1)! + 3(n-2)! - 4(n-3)!.
A374650
a(n) = n! - 2(n-1)! + 3(n-2)! - 4(n-3)!.
Terms
- a(0) =1a(1) =14a(2) =82a(3) =528a(4) =3864a(5) =31920a(6) =294480a(7) =3003840a(8) =33586560a(9) =408602880a(10) =5374252800a(11) =76001587200
External references
- oeis: A374650