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A236324
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Number of (n+1) X (2+1) 0..1 arrays colored with the sum of the upper and lower median values of each 2 X 2 subblock.
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1
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32, 44, 60, 92, 156, 236, 332, 524, 860, 1276, 1852, 2956, 4716, 6956, 10364, 16540, 25820, 38188, 57996, 91980, 141468, 210748, 323964, 509388, 776620, 1166956, 1805244, 2814172, 4273436, 6473068, 10035148, 15530124, 23566812, 35927420
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OFFSET
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1,1
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LINKS
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FORMULA
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Empirical: a(n) = a(n-3) + 4*a(n-4) for n>5.
Empirical g.f.: 4*x*(8 + 11*x + 15*x^2 + 15*x^3 - 4*x^4) / (1 - x^3 - 4*x^4). - Colin Barker, Oct 21 2018
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EXAMPLE
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Some solutions for n=5:
..1..1..0....1..1..0....0..1..1....0..1..0....1..1..1....0..1..1....0..0..1
..1..1..0....0..0..0....1..0..1....1..1..0....0..0..1....0..1..1....0..1..0
..0..0..0....0..1..1....1..1..0....0..0..0....0..0..1....0..0..0....1..0..0
..0..1..1....1..0..1....0..0..0....0..1..1....1..1..1....1..1..0....1..1..1
..0..1..1....0..0..1....0..1..1....0..1..0....1..0..0....1..0..1....0..0..1
..0..0..0....1..1..1....0..1..1....1..1..0....1..0..0....0..1..1....1..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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