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A301966
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Number of 4Xn 0..1 arrays with every element equal to 0, 1 or 4 horizontally or antidiagonally adjacent elements, with upper left element zero.
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1
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8, 34, 40, 64, 111, 219, 443, 904, 1860, 3856, 8015, 16659, 34647, 72088, 150004, 312144, 649555, 1351723, 2812951, 5853784, 12181816, 25350576, 52755019, 109784179, 228462939, 475435704, 989390720, 2058940864, 4284695031
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OFFSET
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1,1
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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) +a(n-3) -a(n-4) -2*a(n-6) +a(n-7) for n>9
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EXAMPLE
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Some solutions for n=5
..0..0..1..0..1. .0..1..0..1..0. .0..0..1..0..1. .0..1..0..1..0
..1..0..0..0..1. .0..1..0..1..0. .1..0..0..0..1. .0..1..0..0..0
..1..0..1..1..1. .0..1..0..1..0. .1..0..1..1..1. .0..1..0..1..0
..1..0..1..0..0. .1..0..1..0..1. .1..0..1..0..1. .0..1..0..1..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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