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A207962
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Number of 4Xn 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 0 1 and 1 0 0 vertically
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1
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9, 81, 297, 989, 3080, 9994, 32358, 104176, 335940, 1083914, 3495930, 11275444, 36368274, 117303034, 378351488, 1220339904, 3936101206, 12695569864, 40948497182, 132075911156, 425999751988, 1374026441136, 4431806698176
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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) = a(n-1) +3*a(n-2) +11*a(n-3) +11*a(n-4) -a(n-5) -20*a(n-6) -27*a(n-7) -5*a(n-8) +20*a(n-9) +13*a(n-10) -3*a(n-11) -4*a(n-12) for n>15
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EXAMPLE
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Some solutions for n=4
..0..0..1..1....1..0..0..1....1..1..1..1....1..1..1..0....1..0..0..1
..1..1..0..0....1..0..0..1....1..1..0..0....0..1..1..0....0..1..1..0
..1..1..1..1....1..0..0..1....0..1..1..1....1..1..1..0....1..0..0..1
..1..1..0..0....1..0..0..1....1..0..0..1....1..1..1..0....1..1..1..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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