%I #5 May 10 2013 12:45:47

%S 1,0,2,18,518,23610,1600982,150451098,18694217558,2966151496410,

%T 584994048653462,140357794553191578,40253455215544778198,

%U 13598018000464234802010,5343837921922909297592342

%N Number of digraphs with labeled vertices and labeled arcs, with n arcs and with no vertex of indegree 0 or outdegree 0.

%F E.g.f.: Sum(Sum((-1)^(n-k)*binomial(n,k)*(exp((k-1)*x)-1)^k*(exp(k*x)-1)^(n-k),k=0..n),n=0..infinity).

%Y Cf. A122399, A122418.

%K easy,nonn

%O 0,3

%A _Vladeta Jovovic_, Sep 03 2006

%E More terms from _Max Alekseyev_, Jul 29 2009