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A236739
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Number of (n+1) X (1+1) 0..2 arrays with the upper median plus the lower median of every 2 X 2 subblock equal.
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1
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81, 267, 833, 2907, 10233, 37467, 139201, 526395, 2012217, 7766523, 30188609, 118025307, 463513593, 1826935707, 7221598657, 28611883131, 113569804473, 451466339643, 1796832336449, 7158277169307, 28539550811769, 113856616625883
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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) = 7*a(n-1) - 2*a(n-2) - 64*a(n-3) + 53*a(n-4) + 229*a(n-5) - 146*a(n-6) - 364*a(n-7) + 96*a(n-8) + 192*a(n-9).
Empirical g.f.: x*(81 - 300*x - 874*x^2 + 2794*x^3 + 4345*x^4 - 7738*x^5 - 10020*x^6 + 5472*x^7 + 6720*x^8) / ((1 - x)*(1 + x)*(1 - 4*x)*(1 - 3*x^2)*(1 - x - 4*x^2)*(1 - 2*x - 4*x^2)). - Colin Barker, Oct 21 2018
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EXAMPLE
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Some solutions for n=5:
..2..0....1..2....1..2....0..2....0..2....1..1....0..2....1..1....1..0....0..1
..0..0....0..1....2..1....2..1....1..1....0..1....0..2....1..2....2..1....2..0
..1..0....1..1....2..0....1..2....0..2....1..2....1..1....1..0....1..1....1..0
..0..0....1..2....1..2....2..0....1..1....1..1....1..0....1..2....1..1....2..0
..0..0....1..1....2..1....2..1....0..2....0..1....1..1....1..1....1..2....1..0
..1..0....0..1....2..1....2..0....1..1....1..1....1..0....1..0....0..1....2..0
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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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