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A236271
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Number of (n+1) X (1+1) 0..2 arrays with the upper median unequal to the lower median in every 2 X 2 subblock.
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1
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42, 208, 1048, 5328, 27168, 138720, 708640, 3620768, 18501536, 94542752, 483118496, 2468772768, 12615641504, 64467060640, 329432556960, 1683430581152, 8602485031328, 43959490084768, 224637040795040, 1147915959163808
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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) = 5*a(n-1) + 4*a(n-2) - 16*a(n-3) - 8*a(n-4).
Empirical g.f.: 2*x*(21 - x - 80*x^2 - 36*x^3) / ((1 - 2*x)*(1 - 3*x - 10*x^2 - 4*x^3)). - Colin Barker, Oct 21 2018
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EXAMPLE
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Some solutions for n=5:
..1..0....1..0....2..1....1..0....0..1....0..2....1..2....1..2....2..1....0..2
..0..1....2..0....0..2....2..0....0..2....2..1....0..2....0..2....1..2....1..2
..0..2....1..2....2..0....2..0....2..1....1..2....0..2....1..2....0..0....2..1
..0..2....2..0....1..0....0..2....0..0....0..2....2..0....1..2....2..2....2..1
..1..0....1..2....1..0....0..2....2..2....2..0....1..0....0..0....0..1....0..0
..2..0....0..0....1..0....2..0....1..0....1..2....1..0....1..2....2..0....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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