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A204625
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Number of (n+1) X 4 0..2 arrays with every 2 X 2 subblock having unequal diagonal elements or unequal antidiagonal elements, and new values 0..2 introduced in row major order.
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1
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768, 43734, 2490558, 141832254, 8077061502, 459972403614, 26194503047262, 1491724252385406, 84950695233299262, 4837771196037723486, 275501337345598245918, 15689246928705157494846, 893471050128160321852158
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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) = 60*a(n-1) - 175*a(n-2) + 68*a(n-3).
Empirical g.f.: 6*x*(128 - 391*x + 153*x^2) / (1 - 60*x + 175*x^2 - 68*x^3). - Colin Barker, Jun 07 2018
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EXAMPLE
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Some solutions for n=3:
..0..1..2..1....0..0..0..0....0..1..0..2....0..0..0..0....0..0..0..1
..2..2..0..0....1..0..1..0....1..2..2..1....1..0..1..0....2..0..1..1
..0..2..2..0....2..1..1..0....1..0..1..1....2..2..1..2....0..0..1..2
..0..1..0..1....2..0..0..0....0..0..2..0....0..0..2..0....2..0..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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