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A207455
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Number of 4 X n 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 0 1 and 1 0 1 vertically.
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1
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8, 64, 168, 760, 2560, 10088, 36456, 138176, 509960, 1910296, 7096320, 26485576, 98590024, 367542080, 1369032168, 5101852856, 19007490560, 70825236904, 263884411560, 983242576576, 3663494987848, 13650146856152, 50859864760320
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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) = a(n-1) + 10*a(n-2) + 3*a(n-3) - 9*a(n-4).
Empirical g.f.: 8*x*(1 + 7*x + 3*x^2 - 9*x^3) / (1 - x - 10*x^2 - 3*x^3 + 9*x^4). - Colin Barker, Jun 23 2018
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EXAMPLE
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Some solutions for n=5:
1 0 1 1 1 1 0 1 1 0 0 1 0 1 0 0 1 0 1 1
1 1 1 1 1 0 1 0 1 0 1 1 1 1 0 0 1 1 1 1
1 1 1 1 1 0 1 0 1 0 0 1 0 1 0 0 1 0 1 0
0 1 1 1 1 0 1 0 1 0 0 1 0 1 0 0 1 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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