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A206130
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Number of (n+1) X 2 0..3 arrays with every 2 X 3 or 3 X 2 subblock having exactly three counterclockwise and three clockwise edge increases.
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1
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256, 564, 3092, 19660, 125236, 797996, 5085012, 32403084, 206481524, 1315758316, 8384382100, 53427641420, 340455961524, 2169481164972, 13824544308692, 88093885500940, 561359021271796, 3577137606898796, 22794527163204372
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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) = 8*a(n-1) - 11*a(n-2) + 4*a(n-3) for n > 5.
Empirical g.f.: 4*x*(64 - 371*x + 349*x^2 + 26*x^3 - 72*x^4) / ((1 - x)*(1 - 7*x + 4*x^2)). - Colin Barker, Jun 13 2018
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EXAMPLE
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Some solutions for n=4:
1 3 2 1 3 0 2 3 3 1 0 1 0 1 3 0 1 2 1 2
2 0 3 2 1 2 3 2 0 2 3 2 2 3 1 2 2 0 2 1
3 2 0 3 2 3 0 3 1 3 0 1 0 1 2 1 0 1 0 3
0 3 3 2 0 1 1 0 3 2 3 2 1 0 0 2 1 2 1 0
2 0 2 3 1 0 0 3 0 3 0 1 2 1 1 3 3 0 2 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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