Number of oriented multigraphs on n labeled arcs (with loops).

A020557

Number of oriented multigraphs on n labeled arcs (with loops).

Terms

    a(0) =1a(1) =2a(2) =15a(3) =203a(4) =4140a(5) =115975a(6) =4213597a(7) =190899322a(8) =10480142147a(9) =682076806159

External references