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A204376
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Number of (n+2) X 5 0..1 arrays with every 3 X 3 subblock having three equal elements in a row horizontally, vertically or nw-to-se diagonally exactly three ways, and new values 0..1 introduced in row major order.
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1
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78, 54, 61, 75, 98, 139, 205, 310, 481, 759, 1206, 1931, 3105, 5002, 8073, 13043, 21082, 34091, 55141, 89198, 144305, 233471, 377742, 611179, 988889, 1600034, 2588889, 4188891, 6777746, 10966603, 17744317, 28710886, 46455169, 75166023, 121621158
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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) +a(n-2) +a(n-3) -a(n-4) -a(n-5) for n>8.
Empirical g.f.: x*(78 - 24*x - 71*x^2 - 118*x^3 - 14*x^4 + 37*x^5 + 8*x^6 + 4*x^7) / ((1 - x)*(1 - x - x^2)*(1 + x + x^2)). - Colin Barker, Jun 07 2018
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EXAMPLE
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Some solutions for n=3:
..0..0..1..0..0....0..1..1..0..0....0..1..1..0..1....0..1..1..0..0
..0..0..1..0..0....0..1..1..1..1....0..1..1..0..1....0..1..1..0..0
..0..0..1..0..0....0..1..1..0..1....0..1..1..0..1....0..1..1..0..0
..0..0..1..0..0....1..1..1..0..1....1..1..1..0..1....0..1..1..0..0
..0..0..1..0..0....0..1..1..0..1....0..1..1..0..1....1..1..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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