The number of simple labeled graphs on 2n nodes whose connected components are even length cycles.

A202065

The number of simple labeled graphs on 2n nodes whose connected components are even length cycles.

Terms

    a(0) =1a(1) =0a(2) =3a(3) =60a(4) =2835a(5) =219240a(6) =25519725a(7) =4169185020a(8) =910363278825

External references