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Number of n X n binary matrices with zero diagonal and x(i,j), x(j,k) and x(k,i) not all equal for i,j,k all different
0

%I #4 Dec 18 2015 18:18:11

%S 1,4,36,450,5172,75204,1353240,27948312

%N Number of n X n binary matrices with zero diagonal and x(i,j), x(j,k) and x(k,i) not all equal for i,j,k all different

%e Some solutions for n=4

%e ..0..1..1..1....0..0..0..0....0..1..1..1....0..0..1..1....0..0..0..1

%e ..1..0..0..1....1..0..0..0....0..0..1..1....0..0..1..1....0..0..1..1

%e ..0..0..0..1....1..1..0..1....0..1..0..0....1..1..0..0....1..1..0..0

%e ..0..0..1..0....1..1..0..0....0..0..0..0....0..1..0..0....1..1..0..0

%K nonn

%O 1,2

%A _R. H. Hardin_ Jun 15 2012