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A221251
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Number of nX4 arrays of occupancy after each element moves to some horizontal or antidiagonal neighbor, with no occupancy greater than 2
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1
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4, 81, 2116, 58081, 1612900, 44903401, 1250753956, 34842328921, 970622980804, 27039303204489, 753252725702500, 20983889126032561, 584562920742585316, 16284579460194091201, 453650957002812576484, 12637673040690140943889
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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) = 39*a(n-1) -356*a(n-2) +1365*a(n-3) -2739*a(n-4) +2904*a(n-5) -1683*a(n-6) +573*a(n-7) -116*a(n-8) +15*a(n-9) -a(n-10)
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EXAMPLE
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Some solutions for n=3
..0..1..2..1....1..1..1..0....1..2..0..0....0..2..2..2....0..1..1..1
..0..2..2..0....1..2..1..1....0..2..2..1....0..0..2..0....1..2..1..0
..0..1..2..1....0..1..2..1....2..1..1..0....0..1..2..1....1..1..2..1
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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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