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

A239770

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

Terms

    a(0) =1a(1) =1a(2) =10a(3) =213a(4) =7720a(5) =420865a(6) =31879296a(7) =3175850965

External references