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A301837
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Number of nX4 0..1 arrays with every element equal to 0, 1 or 2 horizontally or antidiagonally adjacent elements, with upper left element zero.
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1
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8, 81, 678, 5748, 48802, 414385, 3518619, 29877293, 253694309, 2154171994, 18291531681, 155317282580, 1318832060857, 11198483378779, 95088702916552, 807418390272882, 6855961191710593, 58215423910060190, 494319539779559696
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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) = 13*a(n-1) -46*a(n-2) +72*a(n-3) -57*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..1..0. .0..0..1..0. .0..0..0..1. .0..1..0..1. .0..0..1..1
..0..0..1..1. .0..1..1..1. .1..0..1..1. .1..1..0..1. .1..1..0..0
..1..0..0..1. .0..0..1..0. .0..0..0..1. .1..0..1..1. .0..1..0..0
..1..0..1..1. .1..1..0..1. .1..0..1..0. .1..0..1..1. .0..1..0..1
..0..0..0..1. .0..1..1..0. .0..1..0..1. .0..0..1..1. .0..0..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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