A276399 Numerator of n!/(n^n-n).

1, 1, 2, 1, 24, 5, 720, 126, 4480, 6048, 3628800, 95040, 479001600, 55598400, 5806080, 1816214400, 20922789888000, 40327372800, 6402373705728000, 2501955993600, 8911728967680000, 193526296104960000, 1124000727777607680000, 696294353018880000, 2256176006302688870400

Offset

2,3

Links

Chai Wah Wu, Table of n, a(n) for n = 2..453

Natasha Morrison and Alex Scott, Maximizing the number of induced cycles in a graph, Preprint, 2016. See Conj. 1.1.

Example

1, 1/4, 2/21, 1/26, 24/1555, 5/817, 720/299593, 126/134521, 4480/12345679, 6048/43229041, 3628800/67546215517, 95040/4622635937, 479001600/61054982558011, ...

Mathematica

Table[Numerator[n! / (n^n - n)], {n, 2, 30}] (* Vincenzo Librandi, Sep 12 2016 *)

Prog

(Python)
from __future__ import division
from math import factorial
from fractions import gcd
def A276399(n):
    a = factorial(n-1)
    return a//gcd(n**(n-1)-1, a) # Chai Wah Wu, Sep 11 2016
(Magma) [Numerator(Factorial(n)/(n^n-n)): n in [2..25]]; // Vincenzo Librandi, Sep 12 2016

Crossrefs

Cf. A276400.

Sequence in context: A037943 A073876 A355587 * A119828 A328826 A297892

Adjacent sequences: A276396 A276397 A276398 * A276400 A276401 A276402

Keyword

nonn,frac

Author

N. J. A. Sloane, Sep 11 2016

Status

approved