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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
OFFSET
0,3
LINKS
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: A361302 A361309 A223011 * A377631 A109867 A326437
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Aug 06 2014
STATUS
approved