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A208165
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Number of 4Xn 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 0 1 and 0 1 0 vertically
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1
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9, 81, 287, 981, 2920, 9039, 28681, 89623, 278652, 872602, 2730176, 8525256, 26645271, 83307020, 260355204, 813693708, 2543369350, 7949447810, 24845860649, 77657127110, 242721701342, 758634528231, 2371142647768, 7411113488204
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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) +16*a(n-3) +13*a(n-4) +21*a(n-5) -24*a(n-6) -56*a(n-7) -65*a(n-8) +3*a(n-9) +93*a(n-10) +114*a(n-11) +a(n-12) -99*a(n-13) -107*a(n-14) +14*a(n-15) +86*a(n-16) +39*a(n-17) -34*a(n-18) -19*a(n-19) +6*a(n-21) for n>23
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EXAMPLE
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Some solutions for n=4
..1..1..0..0....1..1..1..1....0..1..1..1....0..1..1..0....0..1..1..0
..0..0..1..0....1..0..0..1....1..0..0..1....0..0..1..1....0..1..0..0
..0..1..1..0....1..1..1..1....1..0..0..1....0..1..1..1....0..0..1..0
..0..1..1..0....0..1..1..1....1..0..0..1....0..1..1..0....0..1..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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