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A300460
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Number of nX3 0..1 arrays with every element equal to 2, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
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1
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0, 2, 2, 8, 22, 68, 212, 652, 2017, 6225, 19229, 59393, 183451, 566633, 1750167, 5405795, 16697038, 51572664, 159294072, 492016422, 1519706056, 4693962286, 14498384074, 44781599826, 138318289075, 427227905079, 1319591820767
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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) +2*a(n-2) +3*a(n-3) +a(n-4) +8*a(n-5) +4*a(n-6) -5*a(n-7) -11*a(n-8) +6*a(n-9) -2*a(n-10) -7*a(n-11) -a(n-12) +4*a(n-13) -4*a(n-14) +a(n-15)
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EXAMPLE
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Some solutions for n=5
..0..0..0. .0..0..1. .0..0..0. .0..0..0. .0..0..1. .0..0..0. .0..0..1
..0..0..0. .0..1..1. .0..0..0. .0..0..1. .0..1..1. .0..0..1. .0..1..1
..1..1..0. .1..1..1. .1..1..0. .0..1..1. .0..0..1. .0..1..1. .0..1..1
..1..0..0. .0..0..1. .1..1..0. .1..1..0. .0..1..1. .0..0..1. .0..0..0
..0..0..0. .0..1..1. .1..0..0. .1..0..0. .1..1..1. .0..1..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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