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A221887
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Number of nX3 arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, without 2-loops or left turns
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1
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0, 8, 0, 90, 204, 1297, 4608, 23159, 92312, 425249, 1799292, 7982268, 34469356, 151243634, 657198136, 2872557590, 12512098304, 54609983231, 238067509008, 1038559461306, 4528789386340, 19753331212394, 86145964341528
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OFFSET
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1,2
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 14*a(n-2) +28*a(n-3) +a(n-4) -104*a(n-5) -92*a(n-6) +84*a(n-7) +19*a(n-8) -4*a(n-9) +75*a(n-10) -15*a(n-12) -8*a(n-13) +4*a(n-14)
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EXAMPLE
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Some solutions for n=4
..1..1..0....0..1..0....0..1..0....0..2..1....1..2..0....0..3..1....1..1..1
..0..3..1....1..3..1....1..3..1....1..2..0....0..2..1....1..1..0....0..3..0
..0..3..0....0..1..1....0..2..1....0..1..1....0..1..1....0..2..0....0..3..0
..1..1..1....1..3..0....1..2..0....1..3..0....1..3..0....1..2..1....1..1..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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