Number of topological types of polygons with 2n different sides.

A085990

Number of topological types of polygons with 2n different sides.

Terms

    a(0) =0a(1) =3a(2) =60a(3) =2520a(4) =181440a(5) =19958400a(6) =3113510400a(7) =653837184000

External references