%I #13 Feb 21 2024 12:33:02
%S 1,1,2,1,3,1,4,1,6,1,8,1,18,1,40,1,230,1,4296,1,431206,1,162267272,1,
%T 201636689771,1,777816803942186,1,9865957936943931964,1,
%U 395886667549681689591841,1,53716176608076643470621234239,1,23524515269630339982914646821899537,1,35682168849414944013547274452501768506834,1
%N Number of regular bipartite simple graphs on n nodes.
%C A graph must be regular and bipartite to be a semisymmetric graph.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/SemisymmetricGraph.html">Semisymmetric Graph</a>
%F a(2*n + 1) = 1, a(2*n) = A008324(n). - _Andrew Howroyd_, Sep 05 2018
%Y Cf. A008323, A008324, A008327.
%K nonn
%O 0,3
%A _Eric W. Weisstein_, Aug 13 2003
%E a(10)-a(19) from _Andrew Howroyd_, Sep 05 2018
%E a(0)=1 prepended and a(20) onwards added by _Andrew Howroyd_, Feb 21 2024