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A207748
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Number of nX4 0..1 arrays avoiding 0 0 1 and 0 1 1 horizontally and 0 0 1 and 1 0 0 vertically
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1
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9, 81, 289, 900, 3249, 11449, 42436, 157609, 597529, 2280100, 8791225, 34093921, 133033156, 521345889, 2051093521, 8093881156, 32021313025, 126943276681, 504097160004, 2004526450969, 7979839669321, 31795772223076, 126783929266569
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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) = 9*a(n-1) -15*a(n-2) -70*a(n-3) +208*a(n-4) +148*a(n-5) -795*a(n-6) +15*a(n-7) +1267*a(n-8) -318*a(n-9) -840*a(n-10) +280*a(n-11) +176*a(n-12) -64*a(n-13) for n>14
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EXAMPLE
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Some solutions for n=4
..1..1..1..1....1..0..0..0....0..1..0..0....1..0..0..0....0..1..0..0
..0..0..0..0....1..1..0..1....0..1..0..1....0..1..0..0....0..0..0..0
..1..1..1..1....0..1..0..0....0..0..0..0....1..0..0..0....0..1..0..0
..0..0..0..0....1..1..0..1....0..1..0..1....1..1..0..0....0..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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