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A186478
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Number of (n+1)X6 0..3 arrays with every 2X2 subblock commuting with each of its horizontal and vertical 2X2 subblock neighbors
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1
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4895, 3442, 20224, 25633, 107353, 108025, 433513, 479785, 1793817, 2226665, 7478693, 10225073, 31371137, 46298817, 132181633, 207648469, 559418905, 924724441, 2376589225, 4095459817, 10129319461, 18060113137, 43291468321
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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)+2*a(n-2)-6*a(n-3)+6*a(n-4)-3*a(n-5) for n>16
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EXAMPLE
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Some solutions for 3X6
..1..0..0..0..2..1....0..1..0..1..0..1....0..0..0..0..3..0....2..0..1..0..0..0
..1..0..0..0..0..2....3..0..1..0..1..1....0..0..0..0..0..3....0..2..0..1..0..0
..0..1..0..0..0..0....0..3..0..1..1..2....0..0..0..0..0..0....3..0..2..0..1..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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