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A221375
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Number of nX3 arrays of occupancy after each element stays put or moves to some horizontal, vertical or antidiagonal neighbor, with no occupancy greater than 2
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1
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7, 139, 3017, 68006, 1548941, 35365731, 807887304, 18456843366, 421665253450, 9633337841423, 220081885496712, 5027948655020101, 114867396786410407, 2624232861115617998, 59952562195425809756, 1369660717750392920845
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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) = 53*a(n-1) -1022*a(n-2) +9430*a(n-3) -46832*a(n-4) +127474*a(n-5) -173901*a(n-6) +70397*a(n-7) +60137*a(n-8) -23731*a(n-9) -21147*a(n-10) -4513*a(n-11) -40*a(n-12) +152*a(n-13) +12*a(n-14) for n>15
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EXAMPLE
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Some solutions for n=3
..0..2..1....0..1..2....1..0..1....1..2..0....2..0..1....0..2..1....1..0..1
..2..0..0....1..0..2....2..0..2....1..2..1....0..1..2....0..1..1....1..0..2
..0..2..2....1..1..1....0..2..1....1..0..1....2..0..1....2..0..2....0..2..2
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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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