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%I #4 Dec 18 2015 18:18:11
%S 1,4,25,175,1572,19285,321925,7695406,271013005
%N Number of n X n binary matrices with zero diagonal and x(i,j)+x(j,k)+x(k,i) not equal to one for i,j,k all different
%e Some solutions for n=4
%e ..0..1..1..1....0..0..0..1....0..1..1..1....0..1..1..0....0..1..1..1
%e ..1..0..0..1....0..0..1..1....1..0..1..1....1..0..1..1....1..0..1..0
%e ..1..0..0..1....1..0..0..1....1..1..0..0....0..1..0..1....1..0..0..0
%e ..0..1..1..0....1..1..1..0....1..1..1..0....1..1..0..0....1..1..0..0
%K nonn
%O 1,2
%A _R. H. Hardin_ Jun 16 2012