Number of endofunctions f on [2n] that are self-inverse on [n].

A245141

Number of endofunctions f on [2n] that are self-inverse on [n].

Terms

    a(0) =1a(1) =3a(2) =50a(3) =1626a(4) =83736a(5) =6026120a(6) =571350096a(7) =67996818960

External references