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

A239784

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

Terms

    a(0) =1a(1) =1a(2) =14a(3) =351a(4) =14776a(5) =902605a(6) =75313056a(7) =8194699387

External references