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A233638
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Number of (n+1) X (2+1) 0..2 arrays with every 2 X 2 subblock having the sum of the squares of the edge differences equal to 2.
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1
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90, 534, 3004, 17424, 99380, 572192, 3277236, 18825580, 107963840, 619734876, 3555590252, 20405232856, 117085241588, 671895102796, 3855486448064, 22124270945452, 126955643098236, 728515542322936, 4180454758322084
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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) = 6*a(n-1) + 9*a(n-2) - 67*a(n-3) + 26*a(n-4) + 81*a(n-5) - 48*a(n-6) + 2*a(n-7).
Empirical g.f.: 2*x*(45 - 3*x - 505*x^2 + 312*x^3 + 619*x^4 - 405*x^5 + 17*x^6) / (1 - 6*x - 9*x^2 + 67*x^3 - 26*x^4 - 81*x^5 + 48*x^6 - 2*x^7). - Colin Barker, Oct 11 2018
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EXAMPLE
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Some solutions for n=5:
..0..1..1....0..1..0....1..0..1....1..1..1....1..2..1....1..2..1....1..1..1
..0..0..1....0..1..1....1..0..0....2..1..0....2..2..1....1..1..1....2..2..2
..1..1..1....1..1..2....1..0..1....2..1..1....2..1..1....0..1..0....1..1..1
..2..2..1....2..1..1....1..0..0....2..2..2....2..2..1....1..1..1....0..1..2
..1..2..1....2..1..0....1..1..0....1..2..1....1..2..1....2..2..2....1..1..1
..1..2..2....1..1..0....2..1..0....1..1..1....2..2..2....2..1..1....2..2..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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