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A302416
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Number of 3Xn 0..1 arrays with every element equal to 0, 1, 2 or 5 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.
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1
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4, 25, 30, 66, 142, 289, 599, 1268, 2660, 5558, 11659, 24470, 51293, 107533, 225522, 472918, 991618, 2079349, 4360310, 9143205, 19172527, 40203428, 84303632, 176778210, 370690543, 777310342, 1629961137, 3417905349, 7167090042
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 3*a(n-1) -3*a(n-2) +4*a(n-3) -4*a(n-4) +a(n-5) for n>9
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EXAMPLE
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Some solutions for n=5
..0..0..1..1..0. .0..1..1..0..0. .0..1..0..1..0. .0..1..0..1..0
..1..0..0..0..1. .0..0..1..0..1. .1..0..0..1..0. .0..1..1..1..1
..1..0..1..0..1. .1..0..1..0..0. .0..1..0..1..1. .1..1..0..0..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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