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A301658
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Number of nX4 0..1 arrays with every element equal to 0, 1 or 4 horizontally or vertically adjacent elements, with upper left element zero.
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1
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5, 6, 9, 13, 24, 45, 89, 182, 373, 773, 1604, 3333, 6933, 14422, 30009, 62445, 129944, 270413, 562729, 1171046, 2436965, 5071365, 10553604, 21962245, 45703845, 95110566, 197926889, 411889613, 857150104, 1783745645, 3712008569, 7724760342
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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) -a(n-3) -2*a(n-4) +a(n-5)
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EXAMPLE
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Some solutions for n=5
..0..1..0..1. .0..1..0..1. .0..1..0..1. .0..1..0..1. .0..1..0..1
..1..1..1..0. .1..0..1..0. .1..1..1..0. .1..0..0..0. .1..0..1..0
..0..1..0..1. .0..1..1..1. .0..1..0..1. .0..1..0..1. .0..1..0..1
..1..0..1..0. .1..0..1..0. .1..0..1..0. .1..1..1..0. .1..0..1..0
..0..1..0..1. .0..1..0..1. .1..0..1..0. .0..1..0..1. .0..1..0..1
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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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