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

A239779

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

Terms

    a(0) =1a(1) =1a(2) =12a(3) =267a(4) =9088a(5) =425465a(6) =27039096a(7) =2261637637

External references