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A235892
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Number of (n+1) X (7+1) 0..3 arrays with the minimum plus the upper median equal to the lower median plus the maximum in every 2 X 2 subblock.
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1
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67072, 70168, 76456, 89416, 116872, 177928, 324616, 716296, 1892872, 5818888, 19962376, 73415176, 280984072, 1098775048, 4344969736, 17279810056, 68919294472, 275277478408, 1100310706696, 4399644604936, 17595382168072
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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) - 14*a(n-2) + 8*a(n-3).
G.f.: 8*x*(8384 - 49917*x + 65536*x^2) / ((1 - x)*(1 - 2*x)*(1 - 4*x)).
a(n) = 4*(16002 + 381*2^n + 4^n).
(End)
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EXAMPLE
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Some solutions for n=4:
..2..2..2..3..1..1..0..3....0..2..0..1..2..2..0..1....2..2..2..2..2..1..1..2
..2..2..2..3..1..1..0..3....0..2..0..1..2..2..0..1....2..2..2..2..2..1..1..2
..2..2..2..3..1..1..0..3....0..2..0..1..2..2..0..1....1..1..1..1..1..2..2..1
..2..2..2..3..1..1..0..3....0..2..0..1..2..2..0..1....1..1..1..1..1..2..2..1
..2..2..2..3..1..1..0..3....0..2..0..1..2..2..0..1....2..2..2..2..2..1..1..2
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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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