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A193783
Number of n X n symmetric 0..4 arrays with no element equal to the sum or difference mod 5 of any two of its horizontal and vertical neighbors
1
5, 32, 172, 2836, 91416, 5932132, 772063340, 201054032608, 104742810130844, 109165192335096960, 227605696416524730032, 949334416935490848158628, 7921224347549868400719029840, 132221576468713050783073932552152
OFFSET
1,1
LINKS
EXAMPLE
Some solutions for 4X4
..3..2..3..3....3..3..2..3....4..3..3..3....1..2..2..2....3..1..1..1
..2..2..2..2....3..3..2..2....3..3..2..2....2..2..2..3....1..1..4..1
..3..2..2..3....2..2..3..2....3..2..2..3....2..2..3..3....1..4..1..1
..3..2..3..3....3..2..2..2....3..2..3..2....2..3..3..4....1..1..1..3
CROSSREFS
Sequence in context: A271455 A270423 A272448 * A271398 A006214 A157704
KEYWORD
nonn
AUTHOR
R. H. Hardin Aug 05 2011
STATUS
approved