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A239753 Number of pairs of functions (f,g) on a set of n elements into itself satisfying f(x) = g(f(g(x))). 0

%I #12 Dec 25 2023 17:40:02

%S 1,1,8,87,1312,24685,564336,15168811

%N Number of pairs of functions (f,g) on a set of n elements into itself satisfying f(x) = g(f(g(x))).

%F a(n) <= n^2n. - _Charles R Greathouse IV_, Mar 26 2014

%Y Cf. A000248, A000949.

%K nonn,more

%O 0,3

%A _Chad Brewbaker_, Mar 26 2014

%E a(6)-a(7) from _Giovanni Resta_, Mar 28 2014

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Last modified September 5 22:34 EDT 2024. Contains 375701 sequences. (Running on oeis4.)