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A193786
Number of n X n symmetric 0..7 arrays with no element equal to the sum or difference mod 8 of any two of its horizontal and vertical neighbors
0
8, 225, 12385, 2332419, 1850486123, 6771682819965, 107524741264745861, 7041765967963842788487
OFFSET
1,1
EXAMPLE
Some solutions for 4X4
..6..4..3..5....4..4..5..3....6..2..6..6....2..2..6..2....6..2..2..5
..4..4..5..3....4..4..5..4....2..6..5..2....2..2..6..2....2..2..6..2
..3..5..4..4....5..5..3..4....6..5..6..6....6..6..6..5....2..6..1..6
..5..3..4..5....3..4..4..2....6..2..6..1....2..2..5..6....5..2..6..2
CROSSREFS
Sequence in context: A214383 A220546 A189445 * A213799 A316809 A299655
KEYWORD
nonn
AUTHOR
R. H. Hardin Aug 05 2011
STATUS
approved