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A250951
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Number of (n+1) X (3+1) 0..1 arrays with no 2 X 2 subblock having its maximum diagonal element less than its minimum antidiagonal element.
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1
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209, 2744, 36016, 472712, 6204344, 81431944, 1068793208, 14027896712, 184115958136, 2416519505288, 31716786410360, 416282400363400, 5463700975560056, 71711002733396360, 941205958384596856
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OFFSET
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1,1
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LINKS
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FORMULA
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Empirical: a(n) = 15*a(n-1) - 24*a(n-2) - 8*a(n-3).
Empirical g.f.: x*(209 - 391*x - 128*x^2) / (1 - 15*x + 24*x^2 + 8*x^3). - Colin Barker, Nov 24 2018
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EXAMPLE
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Some solutions for n=3:
1 0 0 1 1 1 0 1 0 1 0 0 1 0 1 1 0 0 1 0
0 0 0 0 1 0 1 1 0 1 0 0 0 0 0 1 1 0 1 1
1 0 0 1 0 1 1 0 1 1 0 1 1 0 0 0 0 0 0 1
0 0 0 1 0 0 1 1 0 1 0 1 1 0 0 0 0 0 1 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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