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A239785 Number of pairs of functions (f,g) from a set of n elements into itself satisfying f(g(g(x))) = f(g(x)). 4
1, 1, 14, 411, 19912, 1412745, 136537056, 17121680443 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..7.

CROSSREFS

Cf. A181162.

Sequence in context: A041367 A041364 A222904 * A275025 A236156 A258392

Adjacent sequences:  A239782 A239783 A239784 * A239786 A239787 A239788

KEYWORD

nonn,more

AUTHOR

Chad Brewbaker, Mar 26 2014

EXTENSIONS

a(6)-a(7) from Giovanni Resta, Mar 28 2014

STATUS

approved

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Last modified February 27 13:18 EST 2020. Contains 332306 sequences. (Running on oeis4.)