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A303803
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Number of nX3 0..1 arrays with every element unequal to 0, 1, 3 or 4 king-move adjacent elements, with upper left element zero.
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1
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3, 7, 9, 15, 27, 47, 83, 161, 321, 641, 1293, 2665, 5603, 11957, 25767, 55917, 122063, 267835, 590085, 1303845, 2886875, 6401619, 14212171, 31580661, 70221799, 156218863, 347655099, 773886975, 1723025065, 3836799089, 8544630497
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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) = 3*a(n-1) -a(n-2) -3*a(n-3) +6*a(n-4) -5*a(n-5) -2*a(n-6) -a(n-7) -6*a(n-8) +4*a(n-9) +2*a(n-10)
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EXAMPLE
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Some solutions for n=5
..0..0..1. .0..0..1. .0..1..1. .0..0..0. .0..0..0. .0..0..0. .0..0..1
..0..0..0. .0..1..1. .1..1..1. .0..0..0. .0..0..0. .0..0..0. .0..0..0
..0..0..0. .1..1..1. .1..1..1. .0..0..0. .0..0..0. .0..0..0. .0..0..0
..0..0..1. .1..1..1. .0..1..1. .0..0..0. .0..0..0. .0..0..1. .0..0..0
..0..1..1. .0..1..1. .0..0..1. .0..0..0. .0..0..1. .0..1..1. .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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