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A236048
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Number of (n+1) X (1+1) 0..2 arrays colored with the difference of the maximum and minimum in each 2 X 2 subblock.
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1
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81, 292, 1112, 3760, 13716, 46828, 169500, 582300, 2096012, 7237244, 25932972, 89903068, 320993612, 1116363900, 3974561132, 13858016796, 49226653068, 171984277180, 609825727660, 2133983154780, 7555901021900, 26474357927164
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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) = 9*a(n-2) + 4*a(n-3) + 24*a(n-4) + 12*a(n-5) + 8*a(n-6) for n > 8.
Empirical g.f.: x*(81 + 292*x + 383*x^2 + 808*x^3 + 596*x^4 + 560*x^5 + 176*x^6 + 64*x^7) / (1 - 9*x^2 - 4*x^3 - 24*x^4 - 12*x^5 - 8*x^6). - Colin Barker, Oct 20 2018
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EXAMPLE
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Some solutions for n=4:
2 2 2 1 0 1 1 1 1 2 2 2 1 0 0 0 2 2 1 0
2 2 2 2 0 1 1 1 2 1 1 1 0 1 1 2 1 1 2 2
2 1 1 0 1 2 0 0 1 0 1 1 2 2 2 1 1 1 2 1
0 1 0 0 2 1 0 0 0 0 0 0 1 2 0 0 1 2 0 1
0 0 0 2 0 0 1 2 0 2 2 1 0 0 0 1 0 1 1 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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