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A186581
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Number of (n+3) X 4 0..2 arrays with every 4 X 4 subblock commuting with each horizontal and vertical neighbor 4 X 4 subblock.
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1
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43046721, 8824, 38608, 192026, 805791, 1728546, 2296065, 2604716, 2927679, 3089510, 3313917, 4090548, 6218902, 9961241, 15014753, 21788652, 31911831, 45586648, 62332637, 84072672, 116767981, 164051247, 227583882, 314652408
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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)-a(n-2)+2*a(n-4)-4*a(n-5)+2*a(n-6)+2*a(n-8)-2*a(n-9) for n>24.
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EXAMPLE
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Some solutions for 5 X 4
..0..1..1..0....1..1..1..2....1..0..0..1....2..0..1..0....1..1..1..0
..0..0..1..1....0..1..1..2....0..1..0..2....0..2..1..0....0..1..1..0
..2..0..0..0....0..0..1..1....0..0..1..0....0..2..1..0....0..0..1..0
..0..2..0..0....0..0..0..0....0..0..0..0....0..2..1..0....0..0..0..0
..0..0..2..0....0..0..0..0....0..0..0..0....0..0..1..2....0..0..0..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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