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A245918
Number of pairs of endofunctions f, g on [n] satisfying f(g^9(i)) = f(i) for all i in [n].
2
1, 1, 10, 207, 6856, 302345, 17812656, 1384059775, 131612023936, 30607186160529, 9712391319942400, 2685817593368889551, 809491207939940828160, 280106645752842329055193, 99175751774345673351479296, 36958774352800067430488661375, 15213494922728791702295969038336
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, 9)*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=9 of A245910.
Sequence in context: A356960 A364989 A245912 * A368441 A211107 A335673
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Aug 06 2014
STATUS
approved