%I

%S 1,1,8,137,7704,1413982

%N Number of n-vertex unlabeled digraphs without endpoints.

%Y Cf. A100548 (labeled case), A004110, A004108, A059166, A059167.

%K more,nonn

%O 1,3

%A Goran Kilibarda, Zoran Maksimovic, _Vladeta Jovovic_, Jan 14 2005