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A232517
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Number of (2+1)X(n+1) 0..2 arrays with every element next to itself plus and minus one within the range 0..2 horizontally, diagonally or antidiagonally, with no adjacent elements equal
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1
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4, 52, 32, 326, 250, 2138, 1956, 13976, 14782, 91760, 109522, 604450, 799026, 3994420, 5761416, 26475334, 41161880, 175967762, 291918330, 1172568978, 2057927044, 7831923864, 14436579566, 52424836208, 100861979186, 351610320834
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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) = 6*a(n-2) +a(n-3) +3*a(n-4) +a(n-5) -2*a(n-6) -2*a(n-7).
Empirical: G.f.: -2*x*(-2-26*x-4*x^2-5*x^3+3*x^4+5*x^5+5*x^6) / ( 1-6*x^2-x^3-3*x^4-x^5+2*x^6+2*x^7 ). - R. J. Mathar, Nov 23 2014
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EXAMPLE
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Some solutions for n=7
..1..0..1..0..1..0..1..0....0..1..2..0..1..2..1..2....2..1..0..1..2..1..2..1
..1..2..1..2..1..2..1..0....2..1..2..0..1..2..1..0....2..1..0..1..2..1..0..1
..1..0..1..0..1..2..1..2....0..1..2..0..1..2..1..0....0..1..0..1..2..1..2..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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