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A318018
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Number of nX2 0..1 arrays with every element unequal to 0, 1, 2 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
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2
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2, 6, 14, 35, 95, 257, 700, 1907, 5202, 14190, 38712, 105614, 288137, 786105, 2144674, 5851173, 15963362, 43551783, 118819435, 324167181, 884403808, 2412860224, 6582846451, 17959543175, 48997829987, 133677528403, 364703530888
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OFFSET
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1,1
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COMMENTS
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Column 2 of A318024.
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LINKS
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R. H. Hardin, Table of n, a(n) for n = 1..210
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FORMULA
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Empirical: a(n) = 2*a(n-1) +3*a(n-2) -2*a(n-3) -2*a(n-4) -a(n-6) +a(n-7)
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EXAMPLE
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Some solutions for n=5
..0..1. .0..0. .0..1. .0..0. .0..0. .0..1. .0..1. .0..0. .0..0. .0..0
..1..1. .0..1. .1..0. .1..1. .1..1. .1..1. .1..1. .0..1. .0..0. .0..1
..0..1. .1..1. .1..1. .1..1. .1..1. .1..1. .1..1. .0..0. .0..0. .1..1
..1..1. .1..1. .0..1. .0..0. .1..0. .0..0. .1..1. .1..0. .0..0. .0..1
..1..1. .1..1. .1..1. .0..1. .1..1. .0..1. .1..0. .0..0. .0..1. .1..0
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CROSSREFS
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Cf. A318024.
Sequence in context: A178320 A297187 A231509 * A025257 A283438 A323027
Adjacent sequences: A318015 A318016 A318017 * A318019 A318020 A318021
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KEYWORD
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nonn
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AUTHOR
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R. H. Hardin, Aug 12 2018
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STATUS
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approved
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