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%I #5 Mar 31 2012 12:36:08
%S 9,141,4743,378999,77470101,43182942669,69704886620367,
%T 343603587128867631,5351921330163734358189,265547472520415711196418101
%N Number of (n+1)X(n+1) 0..2 arrays with diagonal zero and the i,j-th 2X2 subblock sum equal to the j,i-th 2X2 subblock sum
%C Column 2 of A187408
%e Some solutions for 4X4
%e ..0..0..2..1....0..2..0..0....0..2..0..1....0..2..0..2....0..2..0..2
%e ..2..0..2..0....1..0..0..2....2..0..2..0....2..0..1..1....2..0..2..0
%e ..0..2..0..2....0..1..0..1....2..0..0..0....0..1..0..1....0..2..0..1
%e ..2..1..1..0....1..0..2..0....1..0..2..0....2..1..1..0....2..0..1..0
%K nonn
%O 1,1
%A _R. H. Hardin_ Mar 09 2011