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

A239749

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

Terms

    a(0) =1a(1) =1a(2) =6a(3) =87a(4) =2056a(5) =69605a(6) =3201696a(7) =190933435

External references