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A184190
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Half the number of (n+1) X 3 binary arrays with no 2 X 2 subblock containing exactly one 1.
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1
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19, 104, 561, 3050, 16581, 90185, 490546, 2668339, 14514611, 78953456, 429474355, 2336164665, 12707780398, 69125130363, 376012453567, 2045354053808, 11125890031367, 60520294171669, 329205663240430, 1790744248612871
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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) = 7*a(n-1) - 7*a(n-2) - 10*a(n-3) + 10*a(n-4) + 2*a(n-5).
Empirical g.f.: x*(19 - 29*x - 34*x^2 + 41*x^3 + 8*x^4) / (1 - 7*x + 7*x^2 + 10*x^3 - 10*x^4 - 2*x^5). - Colin Barker, Apr 12 2018
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EXAMPLE
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Some solutions for 5 X 3:
..0..1..1....0..1..0....0..0..1....1..0..0....0..1..1....1..1..1....1..1..0
..1..0..1....1..0..1....0..0..1....1..0..0....1..1..1....0..0..1....1..0..1
..1..1..1....1..1..0....1..1..0....1..0..0....0..1..1....1..1..1....1..1..1
..1..1..0....0..0..1....1..1..0....0..1..1....1..1..0....1..1..1....0..1..0
..1..1..1....0..0..1....0..1..0....1..0..0....1..1..0....1..0..0....0..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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