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A238039
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Number of (n+1) X (1+1) 0..2 arrays with the upper median minus the lower median of every 2 X 2 subblock differing from its horizontal and vertical neighbors by exactly one.
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1
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81, 340, 1440, 6064, 25948, 109200, 466296, 1962720, 8385248, 35292928, 150759392, 634547840, 2710688576, 11409244416, 48737830912, 205137173504, 876305679104, 3688361604096, 15755932345856, 66316572940288, 283291082594304
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OFFSET
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1,1
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LINKS
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R. H. Hardin, Table of n, a(n) for n = 1..210
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FORMULA
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Empirical: a(n) = 8*a(n-2) + 152*a(n-4) + 472*a(n-6) + 384*a(n-8).
Empirical g.f.: x*(81 + 340*x + 792*x^2 + 3344*x^3 + 2116*x^4 + 9008*x^5 + 1600*x^6 + 6912*x^7) / ((1 + 6*x^2)*(1 - 14*x^2 - 68*x^4 - 64*x^6)). - Colin Barker, Oct 24 2018
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EXAMPLE
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Some solutions for n=5:
..2..1....2..1....1..0....1..1....2..2....2..1....0..2....0..2....1..1....2..2
..2..2....0..0....1..0....2..0....2..2....0..0....2..2....2..0....0..2....2..0
..1..0....2..0....2..1....1..0....1..1....0..0....1..1....1..2....0..1....1..0
..1..1....1..0....0..2....1..2....0..2....1..2....1..0....1..0....2..1....0..0
..2..2....1..2....0..2....0..2....1..2....0..1....2..0....2..2....2..1....2..1
..2..1....2..1....1..2....2..0....1..1....0..1....2..2....2..0....1..1....2..2
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CROSSREFS
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Column 1 of A238046.
Sequence in context: A237965 A238046 A237958 * A232284 A337044 A337045
Adjacent sequences: A238036 A238037 A238038 * A238040 A238041 A238042
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KEYWORD
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nonn
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AUTHOR
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R. H. Hardin, Feb 17 2014
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STATUS
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approved
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