A239783 Number of pairs of functions (f,g) from a set of n elements into itself satisfying f(g(x)) = f(g(f(x))).

1, 1, 14, 339, 12496, 639005, 42829536, 3624387739

Offset

0,3

Links

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

Crossrefs

Cf. A181162.

Sequence in context: A222984 A278194 A035273 * A020143 A161927 A253457

Adjacent sequences: A239780 A239781 A239782 * A239784 A239785 A239786

Keyword

nonn,more

Author

Chad Brewbaker, Mar 26 2014

Extensions

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

Status

approved