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A276400 Denominator of n!/(n^n-n). 2
1, 4, 21, 26, 1555, 817, 299593, 134521, 12345679, 43229041, 67546215517, 4622635937, 61054982558011, 18617937516193, 5118976599431, 4224061794762749, 128583032925805678351, 655879001624535409, 275941052631578947368421, 286115209221463953761, 2707038020425761202263187 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,2

LINKS

Chai Wah Wu, Table of n, a(n) for n = 2..389

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[Denominator[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 A276400(n):

    a = n**(n-1) - 1

    return a//gcd(factorial(n-1), a) # Chai Wah Wu, Sep 11 2016

(MAGMA) [Denominator(Factorial(n)/(n^n-n)): n in [2..25]]; // Vincenzo Librandi, Sep 12 2016

CROSSREFS

Cf. A276399.

Sequence in context: A133784 A041821 A042429 * A304770 A316513 A329929

Adjacent sequences:  A276397 A276398 A276399 * A276401 A276402 A276403

KEYWORD

nonn,frac

AUTHOR

N. J. A. Sloane, Sep 11 2016

STATUS

approved

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Last modified May 26 00:32 EDT 2020. Contains 334613 sequences. (Running on oeis4.)