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A219129
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Number of 2 X n arrays of the minimum value of corresponding elements and their horizontal, diagonal or antidiagonal neighbors in a random 0..2 2 X n array.
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1
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9, 15, 87, 205, 899, 2521, 9709, 29747, 107261, 344055, 1199763, 3940341, 13507819, 44905025, 152598957, 510467683, 1726955485, 5795447559, 19561570195, 65753998917, 221680877531, 745782497713, 2512791313869, 8457223721011
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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) = 2*a(n-1) + 6*a(n-2) - 6*a(n-3) + 7*a(n-4) - 10*a(n-5) + 6*a(n-6) - 6*a(n-7) - 4*a(n-8).
Empirical g.f.: x*(9 - 3*x + 3*x^2 - 5*x^3 - 6*x^4 - 10*x^6 - 4*x^7) / (1 - 2*x - 6*x^2 + 6*x^3 - 7*x^4 + 10*x^5 - 6*x^6 + 6*x^7 + 4*x^8). - Colin Barker, Jul 25 2018
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EXAMPLE
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Some solutions for n=3:
..0..0..0....0..0..0....2..1..2....2..0..1....0..0..0....1..0..0....2..1..2
..0..2..0....1..0..2....2..1..1....0..0..0....0..0..0....2..0..1....1..1..2
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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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