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A323290 Numerator of the sum of inverse products of cycle sizes in all permutations of [n]. 5
1, 1, 3, 19, 107, 641, 51103, 1897879, 7860361, 505249081, 40865339743, 1355547261301, 244350418462637, 34907820791828741, 1949845703291363567, 1136592473036395958917, 31690844708764028510969, 2681369908698254192692979, 768531714669026186032238737 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..270

EXAMPLE

1/1, 1/1, 3/2, 19/6, 107/12, 641/20, 51103/360, 1897879/2520, 7860361/1680, 505249081/15120, 40865339743/151200, ... = A323290/A323291

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-> numer(b(n)):

seq(a(n), n=0..20);

CROSSREFS

Denominators: A323291.

Cf. A000142, A177208, A177209, A322364, A322365, A322380, A322381, A323339, A323340.

Sequence in context: A305555 A323919 A089164 * A072950 A240123 A130425

Adjacent sequences:  A323287 A323288 A323289 * A323291 A323292 A323293

KEYWORD

nonn,frac

AUTHOR

Alois P. Heinz, Jan 09 2019

STATUS

approved

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Last modified April 25 12:04 EDT 2019. Contains 322456 sequences. (Running on oeis4.)