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A297096
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Number of n X 2 0..1 arrays with no 1 adjacent to 4 king-move neighboring 1s.
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1
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4, 16, 58, 216, 808, 3016, 11264, 42080, 157192, 587200, 2193552, 8194256, 30610528, 114348992, 427163264, 1595715392, 5960970560, 22267862080, 83184051328, 310743185408, 1160815393920, 4336353754624, 16198927050240, 60512876123648
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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) + 6*a(n-3) - 8*a(n-4) - 4*a(n-6).
Empirical g.f.: 2*x*(2 + x^2 - 4*x^3 - 2*x^4 - 2*x^5) / (1 - 4*x + 2*x^2 - 6*x^3 + 8*x^4 + 4*x^6). - Colin Barker, Feb 26 2019
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EXAMPLE
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Some solutions for n=7:
..1..1. .1..1. .0..1. .0..0. .0..1. .0..0. .1..1. .0..0. .1..1. .1..0
..0..1. .0..0. .1..0. .0..0. .1..1. .1..0. .1..0. .0..0. .1..1. .1..0
..1..0. .0..1. .1..1. .0..1. .1..0. .0..1. .0..0. .0..0. .0..0. .1..1
..1..1. .1..0. .0..0. .1..0. .0..1. .0..1. .1..0. .0..0. .1..1. .0..1
..0..1. .1..1. .0..1. .0..0. .0..1. .0..0. .0..0. .0..1. .0..0. .0..1
..1..0. .0..0. .0..1. .0..0. .1..1. .0..1. .1..0. .1..0. .1..1. .0..0
..1..1. .0..0. .0..1. .1..1. .0..1. .0..1. .0..0. .0..0. .0..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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