A226198 a(n) = floor((n-1)!/n).

1, 0, 0, 1, 4, 20, 102, 630, 4480, 36288, 329890, 3326400, 36846276, 444787200, 5811886080, 81729648000, 1230752346352, 19760412672000, 336967037143578, 6082255020441600, 115852476579840000, 2322315553259520000, 48869596859895986086

Offset: 1

Author

Vincenzo Librandi, May 31 2013

Keywords

• nonn

Comments

(h-1)!/h is integer if h belongs to A056653.

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..200

Crossrefs

Cf. A001048 ((n+1)!/n), A056653, A091330 (floor((p-1)!/p), where p is prime), A175787 (prime numbers together with 4).

Programs

Magma

[Floor(Factorial(n-1)/n): n in [1..25]];

Mathematica

Table[Quotient[(n - 1)!, n], {n, 25}]

Extensions

Edited by Bruno Berselli, May 31 2013