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A221403
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Number of 4 X n arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, with no 2-loops and with no occupancy greater than 2.
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0
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0, 38, 144, 89173, 2294372, 247200529, 10874636860, 776880319370, 41186123651894, 2584866896797503, 146335664855961366
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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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EXAMPLE
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Some solutions for n=3
..0..2..0....0..2..0....0..2..0....0..2..0....0..2..0....0..2..0....1..2..1
..2..2..1....2..2..0....2..2..0....1..2..2....1..2..0....0..2..2....1..2..0
..0..2..0....0..2..2....1..2..0....0..2..0....1..2..1....0..2..2....0..2..0
..0..2..1....0..2..0....0..2..1....1..2..0....1..2..0....0..2..0....0..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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