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A245915 Number of pairs of endofunctions f, g on [n] satisfying f(g^6(i)) = f(i) for all i in [n]. 2
1, 1, 12, 297, 11104, 578745, 46097856, 4892935369, 649893820416, 108501530261841, 21500188932505600, 4911081373878751401, 1343217062946070130688, 427404076347462876047113, 154711214699181287350984704, 64222714159878924347124911625 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..150

MAPLE

with(combinat):

b:= proc(n, i) option remember; unapply(`if`(n=0 or i=1, x^n,

      expand(add((i-1)!^j*multinomial(n, n-i*j, i$j)/j!*

      x^(igcd(i, 6)*j)*b(n-i*j, i-1)(x), j=0..n/i))), x)

    end:

a:= n-> add(binomial(n-1, j-1)*n^(n-j)*b(j$2)(n), j=0..n):

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

CROSSREFS

Column k=6 of A245910.

Sequence in context: A041264 A220307 A223011 * A109867 A326437 A303068

Adjacent sequences:  A245912 A245913 A245914 * A245916 A245917 A245918

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Aug 06 2014

STATUS

approved

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Last modified December 7 20:40 EST 2021. Contains 349589 sequences. (Running on oeis4.)