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A207841
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Number of nX4 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 0 0 and 1 1 1 vertically
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1
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10, 100, 180, 780, 2816, 9672, 35952, 130152, 462660, 1691356, 6097536, 21894544, 79589224, 286756120, 1033424532, 3745763500, 13500573120, 48729856032, 176324800080, 635878928776, 2296600176396, 8301910089028, 29954416843008
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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-2) +36*a(n-3) +6*a(n-4) +2*a(n-5) -84*a(n-6) +34*a(n-7) +89*a(n-8) -260*a(n-9) +91*a(n-10) -42*a(n-11) +84*a(n-12) -2*a(n-13) +8*a(n-14) +36*a(n-15) +3*a(n-16) +a(n-18) for n>20
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EXAMPLE
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Some solutions for n=4
..0..1..1..0....0..1..1..0....0..1..0..1....0..1..1..1....0..1..0..1
..0..1..0..1....0..1..0..1....0..1..1..0....1..0..1..0....1..0..1..1
..1..0..1..0....1..0..1..1....1..0..1..1....0..1..0..1....1..0..1..0
..1..1..0..1....1..1..1..0....0..1..0..0....1..0..1..1....0..1..0..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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