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A323291 Denominator of the sum of inverse products of cycle sizes in all permutations of [n]. 5
1, 1, 2, 6, 12, 20, 360, 2520, 1680, 15120, 151200, 554400, 9979200, 129729600, 605404800, 27243216000, 54486432000, 308756448000, 5557616064000, 8122669632000, 351982350720000, 22174888095360000, 25676186215680000, 3740164458750720000, 67322960257512960000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..505

MAPLE

b:= proc(n) option remember; `if`(n=0, 1, add(

      b(n-j)*binomial(n-1, j-1)*(j-1)!/j, j=1..n))

    end:

a:= n-> denom(b(n)):

seq(a(n), n=0..25);

CROSSREFS

See A323290 for more information.

Sequence in context: A099885 A106372 A214916 * A161203 A292768 A184637

Adjacent sequences:  A323288 A323289 A323290 * A323292 A323293 A323294

KEYWORD

nonn,frac

AUTHOR

Alois P. Heinz, Jan 09 2019

STATUS

approved

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Last modified April 19 18:37 EDT 2019. Contains 322290 sequences. (Running on oeis4.)