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A305240
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Number of nX3 0..1 arrays with every element unequal to 0, 1, 2, 4 or 8 king-move adjacent elements, with upper left element zero.
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1
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4, 12, 18, 32, 86, 158, 343, 721, 1520, 3228, 6773, 14334, 30273, 63871, 134918, 284843, 601453, 1270011, 2681563, 5662260, 11955917, 25245070, 53305555, 112555500, 237663066, 501829940, 1059622929, 2237413464, 4724339318
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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) = a(n-1) +2*a(n-2) +2*a(n-3) -a(n-4) -2*a(n-5) -3*a(n-6) -a(n-7) +a(n-8) for n>11
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EXAMPLE
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Some solutions for n=5
..0..0..1. .0..1..1. .0..0..0. .0..0..0. .0..0..0. .0..0..0. .0..1..1
..0..0..1. .0..1..1. .0..0..0. .0..1..0. .0..0..0. .0..1..0. .0..1..1
..0..0..0. .1..1..1. .0..0..0. .0..0..0. .0..0..0. .0..0..0. .1..1..1
..1..0..0. .1..1..1. .0..0..0. .0..0..0. .1..0..0. .1..0..0. .0..1..1
..0..1..0. .1..1..1. .0..1..1. .0..0..0. .0..1..0. .0..1..0. .1..0..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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