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

A239762

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

Terms

    a(0) =1a(1) =1a(2) =10a(3) =159a(4) =3568a(5) =106545a(6) =4062336a(7) =192754009

External references