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A260920
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Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00010101 00101011 or 01010101.
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1
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36, 48, 104, 186, 297, 491, 883, 1489, 2534, 4289, 7421, 12581, 21537, 36634, 62796, 106888, 182812, 311578, 532706, 908294, 1551949, 2647450, 4522307, 7716224, 13177700, 22488756, 38401007, 65541083, 111905468, 191009570, 326112380
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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) = a(n-2) + 3*a(n-4) + 2*a(n-5) + 2*a(n-6) + 3*a(n-7) + a(n-8) for n>10.
Empirical g.f.: x*(36 + 48*x + 68*x^2 + 138*x^3 + 85*x^4 + 89*x^5 + 106*x^6 + 28*x^7 + x^9) / (1 - x^2 - 3*x^4 - 2*x^5 - 2*x^6 - 3*x^7 - x^8). - Colin Barker, Dec 29 2018
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EXAMPLE
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Some solutions for n=4:
..1..0..0....0..1..0....0..0..1....0..1..1....0..1..1....1..0..0....1..0..0
..0..0..0....0..0..1....0..0..0....1..1..0....1..0..0....0..1..0....1..0..1
..1..0..1....0..1..0....1..0..1....0..1..0....0..1..0....1..0..1....0..1..0
..0..1..0....1..0..1....0..1..0....1..0..1....1..0..1....0..1..0....0..0..1
..1..0..0....0..1..0....0..0..1....0..0..1....0..0..0....1..0..1....1..1..0
..0..1..0....1..0..0....0..1..0....1..0..0....1..0..0....0..0..0....1..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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