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A260132
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Number of (n+2) X (2+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00010101 01010101 or 01010111.
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1
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58, 128, 342, 730, 1626, 3928, 8998, 20376, 47424, 109650, 251290, 579658, 1338500, 3080858, 7097716, 16367912, 37715574, 86898450, 200293226, 461601736, 1063705902, 2451421760, 5649587496, 13019565474, 30004282786, 69147284586
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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) + a(n-2) + 5*a(n-3) + a(n-4) - 3*a(n-5) - 3*a(n-6) for n>7.
Empirical g.f.: 2*x*(29 + 35*x + 78*x^2 - 15*x^3 - 72*x^4 - 46*x^5 + 5*x^6) / (1 - x - x^2 - 5*x^3 - x^4 + 3*x^5 + 3*x^6). - Colin Barker, Dec 28 2018
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EXAMPLE
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Some solutions for n=4:
..1..0..1..0....0..0..1..1....1..0..1..0....0..1..0..1....1..0..0..0
..0..1..0..0....0..1..0..1....1..1..0..1....0..0..1..0....0..1..0..1
..1..0..1..0....1..0..1..0....1..0..1..0....0..1..0..1....1..0..1..0
..1..1..0..1....0..1..0..1....0..1..0..1....1..0..1..0....0..1..0..1
..1..0..1..0....1..0..1..0....0..0..1..0....1..1..0..1....1..0..0..0
..0..1..0..1....1..1..0..0....0..1..0..1....1..0..1..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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