%I A067309
%S A067309 0,0,2,9,82,1607,95647
%N A067309 Number of symmetric unlabeled digraphs (unlabeled digraphs with nontrivial 
               automorphism group).
%F A067309 a(n)=A000273(n)-A051504(4)
%e A067309 For n=4 nodes from the 218 (=A000273(4)) unlabeled nonisomorphic digraphs 
               136(=A051504(4)) are asymmetric, so 218-136=82 are somehow symmetric.
%Y A067309 Cf. A000273, A051504.
%Y A067309 Sequence in context: A117581 A123570 A006040 this_sequence A087798 A113146 
               A069234
%Y A067309 Adjacent sequences: A067306 A067307 A067308 this_sequence A067310 A067311 
               A067312
%K A067309 nonn
%O A067309 0,3
%A A067309 Labos E. (labos(AT)ana.sote.hu), Jan 11 2002