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A197103
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Half the number of nX2 0..3 arrays with no element equal to the average of its horizontal and vertical neighbors
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1
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6, 78, 1015, 13526, 181032, 2421376, 32393085, 433365018, 5797636941, 77561969587, 1037640271854, 13881766929498, 185713161140663, 2484509257009467, 33238281011983990, 444668628838107492
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 13*a(n-1) +5*a(n-2) +30*a(n-3) -377*a(n-4) -258*a(n-5) +874*a(n-6) +1758*a(n-7) +685*a(n-8) -2995*a(n-9) -3798*a(n-10) -1113*a(n-11) +2557*a(n-12) +3786*a(n-13) +1955*a(n-14) -639*a(n-15) -1523*a(n-16) -683*a(n-17) +14*a(n-18) +254*a(n-19) +36*a(n-20)
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EXAMPLE
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Some solutions for 4X4
..1..2....0..1....0..1....1..1....0..1....1..2....1..3....1..3....1..1....1..3
..2..0....3..3....0..3....3..3....1..0....1..0....2..3....1..0....3..3....3..0
..0..0....3..3....1..3....3..0....0..3....3..3....1..1....3..1....1..0....1..0
..1..1....1..0....2..0....0..2....2..1....1..0....3..3....1..2....1..2....1..3
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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