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A234826
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Number of (n+1) X (2+1) 0..2 arrays with each 2 X 2 subblock having the number of clockwise edge increases less than or equal to the number of counterclockwise edge increases.
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1
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516, 9207, 161631, 2826144, 49366557, 862112943, 15054585588, 262885602843, 4590533340099, 80160252775488, 1399764282940233, 24442786354729203, 426821718006927396, 7453191942015413679, 130148180682091274007
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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) = 23*a(n-1) - 102*a(n-2) + 93*a(n-3) - 9*a(n-4).
Empirical g.f.: 3*x*(172 - 887*x + 834*x^2 - 81*x^3) / (1 - 23*x + 102*x^2 - 93*x^3 + 9*x^4). - Colin Barker, Oct 16 2018
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EXAMPLE
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Some solutions for n=3:
..1..1..0....1..0..1....0..2..0....0..0..0....1..1..0....0..0..2....1..1..0
..1..1..2....0..0..1....2..2..0....1..1..0....2..2..2....0..1..1....0..0..2
..2..2..1....2..2..0....0..2..2....0..0..2....0..2..2....0..1..2....2..2..2
..2..2..1....2..0..2....0..0..0....1..1..2....0..2..0....2..0..1....2..1..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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