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A283573
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Number of 2Xn 0..1 arrays with no 1 equal to more than one of its horizontal, diagonal and antidiagonal neighbors, with the exception of exactly one element.
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1
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0, 4, 26, 72, 282, 908, 2832, 8856, 26750, 80088, 237190, 695272, 2024064, 5853676, 16835874, 48194664, 137385394, 390201476, 1104636144, 3118021376, 8778028806, 24653647608, 69091665822, 193246772832, 539525988960, 1503796131028
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OFFSET
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1,2
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 2*a(n-1) +5*a(n-2) +2*a(n-3) -17*a(n-4) -24*a(n-5) -16*a(n-6).
Empirical: G.f.: 2*x^2*(2+9*x)/(-1+x+3*x^2+4*x^3)^2 . - R. J. Mathar, Mar 11 2017
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EXAMPLE
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Some solutions for n=4
..0..0..1..1. .0..0..0..0. .1..1..0..0. .1..0..1..1. .0..1..1..1
..0..1..0..1. .0..1..1..1. .1..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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