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%I #5 Dec 18 2015 18:17:43
%S 8,307,28645,7557081,6251248141,18554336578573,227380925067925105
%N Number of n X n symmetric 0..7 arrays with no element equal to the difference mod 8 of any two of its horizontal and vertical neighbors
%e Some solutions for 4X4
%e ..4..4..2..7....4..6..4..0....4..6..0..7....4..6..4..4....4..4..2..7
%e ..4..4..7..7....6..4..6..5....6..4..0..6....6..4..7..7....4..4..4..4
%e ..2..7..2..4....4..6..5..7....0..0..7..4....4..7..7..4....2..4..7..6
%e ..7..7..4..7....0..5..7..3....7..6..4..7....4..7..4..2....7..4..6..3
%K nonn
%O 1,1
%A _R. H. Hardin_ Aug 05 2011