%I #12 Dec 06 2020 17:17:47

%S 1,1,1,7,136,8001,1445297,863488287

%N Number of asymmetric digraphs with n nodes.

%D F. Harary and E. M. Palmer, Graphical Enumeration, Academic Press, NY, 1973, p. 231.

%D P. K. Stockmeyer, The enumeration of graphs with prescribed automorphism group, Dissertation, Univ. of Michigan, Ann Arbor, 1971.

%F a(n) = A000273(n) - A067309(n). - _Andrew Howroyd_, Dec 06 2020

%Y Cf. A000273 (digraphs), A003400 (asymmetric graphs), A030242 (asymmetric relations), A067309.

%K hard,nonn,nice

%O 0,4

%A _Vladeta Jovovic_

%E a(6) from _Christian G. Bower_ Dec 15 1999

%E a(7) from _Andrew Howroyd_, Dec 06 2020