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A302311
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Number of 3 X n 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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1
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4, 6, 13, 26, 48, 121, 275, 600, 1296, 2998, 6731, 15022, 33412, 75480, 169232, 379265, 848913, 1907065, 4276079, 9589159, 21494910, 48224727, 108142434, 242526545, 543834226, 1219737296, 2735350513, 6134430103, 13756843652, 30852213480
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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) = a(n-1) +3*a(n-2) -a(n-3) +8*a(n-4) -7*a(n-5) -22*a(n-6) +9*a(n-7) -14*a(n-8) +10*a(n-9) +39*a(n-10) -19*a(n-11) +6*a(n-12) -18*a(n-14) +9*a(n-15) for n>16.
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EXAMPLE
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Some solutions for n=5
..0..1..0..1..0. .0..0..1..0..1. .0..0..1..0..1. .0..1..1..1..0
..0..1..0..1..1. .0..1..0..0..1. .1..1..1..0..0. .0..1..0..1..0
..0..1..0..1..0. .0..1..0..1..0. .0..0..1..0..1. .0..1..0..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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