Consider the family of multigraphs enriched by the species of involutions. Sequence gives number of those multigraphs with n labeled edges.

A099696

Consider the family of multigraphs enriched by the species of involutions. Sequence gives number of those multigraphs with n labeled edges.

Terms

    a(0) =1a(1) =1a(2) =4a(3) =25a(4) =244a(5) =3380a(6) =62133a(7) =1440382a(8) =40673705a(9) =1364815169a(10) =53415511305

External references