Consider the family of directed multigraphs enriched by the species of involutions. Sequence gives number of those multigraphs with n labeled arcs.
A099699
Consider the family of directed multigraphs enriched by the species of involutions. Sequence gives number of those multigraphs with n labeled arcs.
Terms
- a(0) =1a(1) =1a(2) =8a(3) =108a(4) =2200a(5) =61708a(6) =2249268a(7) =102377404a(8) =5651999688a(9) =370171228504
External references
- oeis: A099699