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A251928
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Number of length n+2 0..1 arrays with the sum of the maximum minus the median of adjacent triples multiplied by some arrangement of +-1 equal to zero.
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1
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5, 10, 18, 34, 68, 136, 268, 528, 1048, 2088, 4160, 8288, 16528, 32992, 65888, 131616, 262976, 525568, 1050560, 2100224, 4199040, 8395904, 16788480, 33571840, 67135744, 134259200, 268499456, 536969728, 1073894400, 2147719168, 4295330816
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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) = 4*a(n-1) - 6*a(n-2) + 6*a(n-3) - 4*a(n-4).
Empirical g.f.: x*(5 - 10*x + 8*x^2 - 8*x^3) / ((1 - 2*x)*(1 - 2*x + 2*x^2 - 2*x^3)). - Colin Barker, Dec 01 2018
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EXAMPLE
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Some solutions for n=6:
..1....1....1....1....1....1....0....1....0....0....0....1....0....0....1....0
..1....0....0....0....1....1....0....1....1....1....1....1....0....1....1....1
..0....0....1....1....1....1....1....1....1....1....1....0....1....0....1....0
..0....0....1....0....0....1....0....1....0....0....1....0....0....1....1....1
..0....0....0....0....1....1....1....1....0....1....0....1....0....0....1....0
..0....0....0....1....1....0....0....0....1....1....1....0....1....0....1....0
..0....1....0....0....0....1....1....0....0....0....0....1....1....1....1....0
..1....1....1....1....1....1....0....1....0....1....0....0....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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