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A302310
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Number of 2Xn 0..1 arrays with every element equal to 0, 1, 3 or 4 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.
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4
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2, 3, 11, 21, 31, 113, 363, 813, 1751, 5001, 14051, 34053, 82063, 218273, 579291, 1452381, 3638471, 9447993, 24526163, 62318133, 158325631, 407598161, 1049289291, 2679681933, 6843284663, 17562012393, 45069368771, 115317418341
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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-2) +4*a(n-3) +12*a(n-4) -16*a(n-5) for n>6
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EXAMPLE
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Some solutions for n=5
..0..1..0..0..1. .0..1..0..1..0. .0..1..0..1..1. .0..1..0..1..0
..0..0..1..0..1. .1..0..0..1..0. .0..1..0..0..0. .0..1..1..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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