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A237938
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Number of (n+1) X (1+1) 0..2 arrays with the maximum minus the minimum of every 2 X 2 subblock equal.
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1
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81, 437, 2417, 13893, 81245, 482409, 2893685, 17487137, 106223237, 647551889, 3957272037, 24224070993, 148455289413, 910505201009, 5587258627429, 34298159298769, 210595144024709, 1293294251436721, 7943185773864101
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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-1) - a(n-2) - 64*a(n-3) - 14*a(n-4) + 88*a(n-5) + 8*a(n-6) - 24*a(n-7).
Empirical g.f.: x*(81 - 211*x - 998*x^2 + 178*x^3 + 1620*x^4 + 20*x^5 - 456*x^6) / ((1 - x)*(1 - 2*x - 8*x^2 - 4*x^3)*(1 - 5*x - 8*x^2 + 6*x^3)). - Colin Barker, Oct 24 2018
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EXAMPLE
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Some solutions for n=5:
..2..2....0..1....2..2....1..1....2..0....2..2....1..2....1..0....1..2....0..1
..2..0....1..2....0..1....0..2....1..0....0..1....2..0....0..2....2..0....0..2
..1..0....0..1....0..2....0..1....1..2....2..1....0..1....0..2....0..2....0..0
..2..2....2..2....2..2....2..2....0..2....2..0....0..2....2..1....0..0....1..2
..1..0....1..0....0..2....0..1....2..1....1..1....2..1....1..0....0..2....0..0
..1..2....2..2....0..1....2..2....2..0....2..0....0..1....1..2....1..1....2..0
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CROSSREFS
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Column 1 of A237945.
Sequence in context: A237308 A237301 A237945 * A017630 A270538 A230064
Adjacent sequences: A237935 A237936 A237937 * A237939 A237940 A237941
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KEYWORD
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nonn
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AUTHOR
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R. H. Hardin, Feb 16 2014
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STATUS
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approved
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