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A234116
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Number of (n+1) X (2+1) 0..2 arrays with every 2 X 2 subblock having the absolute values of all six edge and diagonal differences no larger than 1.
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1
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145, 1361, 12593, 116801, 1082977, 10041953, 93113761, 863396401, 8005833073, 74233997105, 688333901137, 6382568345057, 59182293086657, 548767146042305, 5088437180610625, 47182476443409233, 437498981379983185
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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) = 10*a(n-1) - 4*a(n-2) - 26*a(n-3) + 5*a(n-4).
Empirical g.f.: x*(145 - 89*x - 437*x^2 + 85*x^3) / (1 - 10*x + 4*x^2 + 26*x^3 - 5*x^4). - Colin Barker, Oct 12 2018
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EXAMPLE
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Some solutions for n=4:
..1..1..2....1..1..1....0..1..1....1..1..1....1..2..1....0..0..1....0..0..1
..2..1..2....1..1..2....1..0..1....2..1..0....2..2..2....0..1..0....0..0..1
..1..1..1....2..2..1....1..0..1....1..1..1....1..1..2....0..0..1....0..0..0
..2..2..1....1..1..2....1..0..0....2..1..2....0..1..2....1..1..1....0..0..1
..1..2..1....2..2..1....0..1..1....2..1..2....1..1..1....1..1..1....0..1..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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