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A235843
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Number of (n+1) X (1+1) 0..3 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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156, 1584, 16228, 166816, 1716484, 17668128, 181881988, 1872430816, 19276479364, 198450294432, 2043038387332, 21033017293408, 216534315178372, 2229214808561184, 22949705750645380, 236266598507573728
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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) = 14*a(n-1) - 31*a(n-2) - 94*a(n-3) + 192*a(n-4) + 192*a(n-5).
Empirical g.f.: 4*x*(39 - 150*x - 278*x^2 + 848*x^3 + 768*x^4) / (1 - 14*x + 31*x^2 + 94*x^3 - 192*x^4 - 192*x^5). - Colin Barker, Oct 19 2018
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EXAMPLE
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Some solutions for n=4:
..2..0....2..3....0..1....1..0....0..2....0..1....2..3....0..2....0..2....1..0
..1..0....0..1....3..0....3..0....0..2....1..0....1..3....3..0....1..3....3..2
..0..2....0..2....0..3....0..3....2..0....2..0....3..0....1..0....0..3....0..3
..2..1....2..0....0..2....2..3....2..1....1..2....1..3....3..0....0..1....2..1
..0..2....3..1....2..0....3..1....3..3....1..2....1..3....3..0....2..3....3..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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