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A295914
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Number of n X 4 0..1 arrays with each 1 adjacent to 0 or 3 king-move neighboring 1s.
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1
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8, 28, 115, 467, 1880, 7604, 30721, 124117, 501512, 2026304, 8187195, 33079959, 133657824, 540037688, 2181994609, 8816237625, 35621557528, 143927081684, 581530015059, 2349642293451, 9493609553944, 38358444014860, 154985331853649
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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) = 2*a(n-1) + 7*a(n-2) + 6*a(n-3) - 3*a(n-4) - 4*a(n-5) + a(n-6).
Empirical g.f.: x*(8 + 12*x + 3*x^2 - 7*x^3 - 3*x^4 + x^5) / ((1 + x)*(1 - 3*x - 4*x^2 - 2*x^3 + 5*x^4 - x^5)). - Colin Barker, Feb 22 2019
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EXAMPLE
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Some solutions for n=7:
..1..0..0..0. .0..1..0..0. .0..0..0..1. .0..0..0..1. .0..0..0..1
..0..0..1..0. .0..0..0..0. .1..0..0..0. .1..0..0..0. .1..1..0..0
..0..0..0..0. .0..0..0..0. .0..0..0..0. .0..0..1..0. .1..1..0..0
..1..1..0..0. .0..0..0..0. .0..1..0..1. .0..0..0..0. .0..0..0..1
..1..1..0..0. .0..0..1..0. .0..0..0..0. .0..0..0..0. .1..0..0..0
..0..0..0..1. .1..0..0..0. .0..0..0..0. .0..0..0..0. .0..0..0..0
..0..0..0..0. .0..0..1..0. .0..0..0..0. .0..0..0..1. .0..1..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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