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A221134
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Number of nX3 arrays of occupancy after each element moves to some horizontal or vertical neighbor, with no occupancy greater than 2
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1
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2, 49, 656, 12544, 200072, 3485689, 58132316, 990486784, 16699002692, 282999528529, 4783766470826, 80965479678724, 1369496232351362, 23171487659654569, 391996208325992186, 6631958618350959364
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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) = 21*a(n-1) -1450*a(n-3) +4782*a(n-4) -372*a(n-5) +1450*a(n-6) +69*a(n-8) +a(n-9)
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EXAMPLE
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Some solutions for n=3
..2..1..1....1..2..0....0..2..2....2..1..0....0..2..2....0..1..2....0..2..2
..1..0..1....1..2..0....1..1..1....2..1..2....0..2..1....2..0..1....1..0..1
..0..2..1....1..2..0....0..1..1....0..0..1....0..2..0....2..1..0....2..1..0
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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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