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%I #5 Nov 25 2018 13:56:21
%S 1,1,1,2,1,5,1,20,1,139,1,1777,1,42295,1,1888140,1,158903233,1,
%T 25355226287,1,7707419775769,1
%N Half the number of n X n binary matrices, symmetric about the diagonal and under 90-degree rotation, having equal row sums.
%K nonn
%O 1,4
%A _R. H. Hardin_, Jul 28 2008
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