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

A239755

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

Terms

    a(0) =1a(1) =1a(2) =8a(3) =123a(4) =2776a(5) =86265a(6) =3498336a(7) =179365669

External references