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A297088
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Number of n X 2 0..1 arrays with no 1 adjacent to 3 king-move neighboring 1s.
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1
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4, 15, 45, 152, 511, 1681, 5588, 18575, 61621, 204608, 679407, 2255577, 7488924, 24864735, 82554557, 274095080, 910042783, 3021494049, 10031871012, 33307511407, 110586567109, 367166113104, 1219053634447, 4047464337257
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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) = 4*a(n-1) - 2*a(n-2) + 3*a(n-3) - 14*a(n-4) + 4*a(n-5).
Empirical g.f.: x*(4 - x - 7*x^2 - 10*x^3 + 4*x^4) / (1 - 4*x + 2*x^2 - 3*x^3 + 14*x^4 - 4*x^5). - Colin Barker, Feb 26 2019
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EXAMPLE
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Some solutions for n=7:
..1..0. .1..1. .1..0. .0..1. .1..1. .0..0. .0..1. .0..1. .1..0. .0..0
..0..0. .0..1. .0..0. .0..0. .0..0. .0..1. .1..0. .1..0. .1..0. .1..0
..0..0. .1..1. .1..1. .0..1. .1..0. .1..1. .0..0. .0..0. .0..0. .0..0
..1..0. .1..1. .0..0. .0..0. .0..0. .0..0. .1..0. .1..0. .1..0. .0..1
..0..1. .1..1. .0..1. .1..0. .0..0. .1..0. .1..0. .1..0. .0..0. .0..0
..1..0. .0..1. .1..1. .1..0. .1..0. .0..0. .0..0. .0..0. .0..1. .0..1
..1..0. .0..0. .0..0. .0..0. .0..0. .1..0. .1..0. .0..0. .1..1. .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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