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A232061
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Number of nX4 0..2 arrays with every 0 next to a 1 and every 1 next to a 2 horizontally or vertically, with no adjacent values equal
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1
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6, 30, 130, 534, 2230, 9310, 38870, 162278, 677510, 2828606, 11809446, 49304494, 205846518, 859410282, 3588042398, 14980095674, 62541977366, 261113080850, 1090148470882, 4551375536978, 19002016543538, 79333517919430
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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) = 4*a(n-1) +a(n-2) -4*a(n-4) -3*a(n-5) +a(n-7) +3*a(n-8) -a(n-11)
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EXAMPLE
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Some solutions for n=7
..1..0..1..2....0..1..0..1....1..2..1..0....2..0..1..2....2..1..2..1
..2..1..0..1....1..2..1..2....0..1..0..2....0..2..0..1....1..2..1..0
..1..2..1..0....2..1..2..1....1..0..2..1....1..0..1..0....2..1..2..1
..2..0..2..1....1..0..1..2....2..1..0..2....2..1..2..1....1..2..1..0
..0..1..0..2....2..1..0..1....1..2..1..0....0..2..1..2....2..1..2..1
..1..2..1..0....1..2..1..2....2..1..2..1....1..0..2..1....1..2..1..0
..2..1..0..2....0..1..2..1....1..0..1..2....2..1..0..2....0..1..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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