Certain subgraphs of a directed graph (binomial transform of A005321).

A005331

Certain subgraphs of a directed graph (binomial transform of A005321).

Terms

    a(0) =1a(1) =2a(2) =5a(3) =20a(4) =179a(5) =4082a(6) =218225a(7) =25316720a(8) =6135834479

External references