%I #5 Nov 25 2018 13:45:22
%S 1,1,1,4,3,13,43,580,1897,23851,149041,14348161,74552521,7849966951,
%T 311500453881,64690704744716,2466747100788601,493809829542170401
%N Half the number of n X n binary matrices, symmetric under 90-degree rotation, having equal row sums.
%K nonn
%O 1,4
%A _R. H. Hardin_, Jul 28 2008
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