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A183399
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Half the number of n X 3 binary arrays with no element equal to a strict majority of its diagonal and antidiagonal neighbors.
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1
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4, 2, 6, 32, 110, 450, 1680, 6498, 24794, 95048, 364030, 1394450, 5342640, 20467202, 78415506, 300419072, 1150965830, 4409544050, 16893761040, 64722982898, 247965235594, 949998793608, 3639613683310, 13944005214050, 53421954623280
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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) = 5*a(n-1) - 23*a(n-3) + 15*a(n-4) + 40*a(n-5) - 46*a(n-6) + 20*a(n-8) - 8*a(n-9) for n>10.
Empirical g.f.: 2*x*(2 - 9*x - 2*x^2 + 47*x^3 - 32*x^4 - 76*x^5 + 90*x^6 - 40*x^8 + 16*x^9) / ((1 - 5*x + 5*x^2 - 2*x^3)*(1 - 5*x^2 + 10*x^4 - 4*x^6)). - Colin Barker, Mar 28 2018
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EXAMPLE
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Some solutions with a(1,1)=0 for 4 X 3:
..0..1..0....0..0..0....0..1..0....0..0..0....0..1..0....0..0..0....0..1..0
..1..1..0....1..1..1....0..1..0....1..1..1....0..1..0....1..1..1....0..1..1
..0..0..0....0..0..1....1..0..0....1..0..1....0..1..1....0..1..1....1..0..0
..1..1..1....1..0..1....1..0..1....1..0..1....0..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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