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A232401
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Number of (n+1)X(3+1) 0..2 arrays with every element next to itself plus and minus one within the range 0..2 horizontally or vertically, with no adjacent elements equal
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1
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8, 20, 52, 176, 484, 1500, 4416, 13220, 39524, 117892, 352408, 1052272, 3143372, 9389000, 28044172, 83767512, 250208044, 747361736, 2232332800, 6667874240, 19916631536, 59490043068, 177693992608, 530763654360, 1585366282080
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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) = 2*a(n-1) +4*a(n-2) +a(n-3) -10*a(n-4) -9*a(n-5) +16*a(n-7) +4*a(n-8) -a(n-9) -4*a(n-10) -a(n-11) -a(n-12)
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EXAMPLE
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Some solutions for n=4
..2..1..2..1....0..1..2..1....1..2..1..0....1..0..1..2....2..1..0..1
..1..0..1..0....1..0..1..0....0..1..0..1....2..1..0..1....1..0..1..2
..2..1..0..1....2..1..2..1....1..2..1..2....1..0..1..2....0..2..0..1
..1..0..1..2....1..0..1..0....0..1..2..1....0..1..0..1....2..1..2..0
..2..1..0..1....2..1..2..1....1..2..1..0....1..2..1..2....1..0..1..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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