Number of labeled 2-regular graphs with no multiple edges, but loops are allowed (i.e., each vertex is endpoint of two (usual) edges or one loop).

A108246

Number of labeled 2-regular graphs with no multiple edges, but loops are allowed (i.e., each vertex is endpoint of two (usual) edges or one loop).

Terms

    a(0) =1a(1) =1a(2) =1a(3) =2a(4) =8a(5) =38a(6) =208a(7) =1348a(8) =10126a(9) =86174a(10) =819134a(11) =8604404a(12) =98981944a(13) =1237575268a(14) =16710431992a(15) =242337783032

External references