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%I #14 May 31 2019 05:36:18
%S 1,0,0,1,6,28,252,4726,150324,8308928,817860888,144938364368,
%T 46784208920560,27789645300385184,30630702203393521120,
%U 63070163901389334212336,243902725979609232729020320,1779250465648201682685291759744
%N a(n) is the number of unlabeled simple graphs with n vertices that have no automorphisms of odd parity.
%H Brendan McKay, <a href="http://users.cecs.anu.edu.au/~bdm/data/graphs.html">Isoclasses of simple graphs</a>
%t (* This assumes you have Brendan McKay's files listing isoclasses of simple graphs (see link), and starts from a(2), as there is no graph1.g6 *)
%t Table[
%t Length@ Select[
%t Import["graph" <> ToString[i] <> ".g6"],
%t Function[g,
%t ! AnyTrue[GroupElements[GraphAutomorphismGroup[g]],
%t Apply[Times, (-1)^(Length /@ First[#] - 1)] == -1 &]
%t ]
%t ],
%t {i, 2, 9}
%t ]
%K nonn
%O 1,5
%A _Mariano Suárez-Álvarez_, Jan 12 2017
%E More terms from _Ira M. Gessel_, May 30 2019
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