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A259955
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Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000000 00000001 or 00001001.
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1
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34, 67, 155, 353, 808, 1884, 4340, 9925, 22799, 52515, 120848, 277830, 638728, 1468871, 3378335, 7769445, 17866796, 41087200, 94488464, 217296769, 499716771, 1149192279, 2642787772, 6077609506, 13976655996, 32142038875, 73916854091
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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-1) + 3*a(n-3) + 5*a(n-4) + 6*a(n-5) + 6*a(n-6) + 2*a(n-7) for n>8.
Empirical g.f.: x*(34 + 33*x + 88*x^2 + 96*x^3 + 84*x^4 + 72*x^5 + 16*x^6 - 4*x^7) / (1 - x - 3*x^3 - 5*x^4 - 6*x^5 - 6*x^6 - 2*x^7). - Colin Barker, Dec 27 2018
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EXAMPLE
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Some solutions for n=4:
..1..0..0....0..0..0....0..0..0....0..0..0....0..1..0....1..0..0....1..0..0
..0..0..0....0..0..1....0..0..0....0..0..0....0..1..0....0..1..0....0..0..0
..0..1..0....0..0..0....1..0..0....0..0..0....0..0..0....0..0..0....0..1..0
..0..0..0....0..0..0....0..0..0....1..0..0....0..0..0....0..0..0....0..1..0
..0..0..1....1..0..0....0..1..0....0..0..0....1..0..0....1..0..0....0..0..0
..1..0..0....0..0..0....0..0..1....0..0..0....0..0..0....0..0..0....1..0..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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