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A300541
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Number of nX3 0..1 arrays with every element equal to 1, 2, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
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1
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1, 11, 71, 450, 2879, 18365, 117146, 747252, 4766519, 30404411, 193941921, 1237105726, 7891179813, 50335810076, 321079209472, 2048081844697, 13064188271417, 83333102938721, 531560469056352, 3390687761515265
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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) = 5*a(n-1) +9*a(n-2) -8*a(n-4) -3*a(n-5) +4*a(n-6) +4*a(n-7) +2*a(n-8) for n>10
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EXAMPLE
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Some solutions for n=5
..0..0..1. .0..0..1. .0..0..0. .0..0..0. .0..0..1. .0..0..0. .0..0..1
..1..0..1. .1..0..1. .1..1..1. .1..1..0. .0..1..0. .1..1..1. .0..1..0
..1..1..1. .1..0..1. .0..0..1. .0..1..0. .1..0..1. .1..0..1. .1..0..1
..0..1..1. .0..0..1. .0..1..0. .0..1..0. .1..1..1. .1..0..1. .1..0..1
..0..0..1. .0..0..0. .0..0..0. .0..0..0. .1..0..0. .0..0..0. .1..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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