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%I #5 Dec 18 2015 18:17:41
%S 7,216,19002,5354628,4811755110,13792037832498,126348317344567128
%N Number of n X n symmetric 0..6 arrays with no element equal to the sum mod 7 of any two of its horizontal and vertical neighbors
%e Some solutions for 4X4
%e ..0..2..3..2....0..3..4..6....0..1..6..4....0..1..6..0....0..2..4..0
%e ..2..0..6..0....3..0..2..6....1..0..3..1....1..0..3..6....2..0..3..5
%e ..3..6..0..2....4..2..0..2....6..3..0..2....6..3..1..2....4..3..2..4
%e ..2..0..2..5....6..6..2..1....4..1..2..0....0..6..2..0....0..5..4..0
%K nonn
%O 1,1
%A _R. H. Hardin_ Jul 18 2011
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