A239765 Number of pairs of functions (f,g) from a set of n elements into itself satisfying f(f(g(x))) = g(g(g(x))).

1, 1, 10, 189, 6304, 315065, 21848976, 1992930037

Offset

0,3

Links

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

Crossrefs

Cf. A181162.

Sequence in context: A121973 A223146 A365175 * A006409 A173813 A249643

Adjacent sequences: A239762 A239763 A239764 * A239766 A239767 A239768

Keyword

nonn,more

Author

Chad Brewbaker, Mar 26 2014

Extensions

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

Status

approved