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A206745
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Number of (n+1) X 2 0..3 arrays with every 2 X 3 or 3 X 2 subblock having an equal number of clockwise and counterclockwise edge increases.
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1
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256, 1888, 15680, 139744, 1289472, 12105120, 114566336, 1088409696, 10358308480, 98658758944, 940033716800, 8958289929184, 85376964317184, 813714139891872, 7755506295392192, 73918257610362720, 704522374079236480
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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) = 15*a(n-1) - 55*a(n-2) + 17*a(n-3) + 108*a(n-4) - 84*a(n-5).
Empirical g.f.: 32*x*(8 - 61*x + 45*x^2 + 126*x^3 - 126*x^4) / ((1 - x)*(1 - 3*x - 6*x^2)*(1 - 11*x + 14*x^2)). - Colin Barker, Jun 17 2018
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EXAMPLE
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Some solutions for n=4:
..1..0....2..3....1..1....1..1....2..3....1..1....0..0....3..3....0..3....1..3
..2..0....3..0....2..2....1..3....1..1....1..2....1..0....1..1....1..1....2..2
..1..0....0..2....1..1....3..3....2..3....1..2....0..1....1..3....3..2....0..3
..1..3....1..3....0..0....2..2....0..3....3..0....1..3....2..0....0..2....2..2
..0..0....2..0....0..0....0..2....1..3....1..2....3..0....0..1....0..3....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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