Number of ordered oriented multigraphs on n labeled arcs (without loops).

A020560

Number of ordered oriented multigraphs on n labeled arcs (without loops).

Terms

    a(0) =1a(1) =1a(2) =8a(3) =110a(4) =2262a(5) =63822a(6) =2335856a(7) =106643980a(8) =5901564892a(9) =387251339836

External references