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A245505
Number of endofunctions f on [n] such that f^9(i) = f(i) for all i in [n].
2
1, 1, 4, 19, 116, 901, 8422, 89755, 1066088, 14154409, 212952266, 3646226959, 69912304156, 1460516349709, 32480282189006, 759186766079011, 18569220500830928, 475114325555073745, 12719547174925542034, 356098625214192355735, 10413932958067814029316
OFFSET
0,3
LINKS
FORMULA
E.g.f.: exp(Sum_{j=0..3} (x*exp(x))^(2^j)/(2^j)).
MAPLE
egf:= exp(add((x*exp(x))^(2^j)/(2^j), j=0..3)):
a:= n-> n!*coeff(series(egf, x, n+1), x, n):
seq(a(n), n=0..25);
CROSSREFS
Column k=9 of A245501.
Sequence in context: A217989 A281817 A060907 * A247056 A163859 A197660
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Jul 24 2014
STATUS
approved