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A205186
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Number of (n+1) X (n+1) 0..1 arrays with the number of clockwise edge increases in every 2 X 2 subblock differing from each horizontal or vertical neighbor.
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0
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16, 40, 124, 256, 736, 1408, 3904, 7168, 19456, 34816, 93184, 163840, 434176, 753664, 1982464, 3407872, 8912896, 15204352, 39583744, 67108864, 174063616, 293601280, 759169024, 1275068416, 3288334336
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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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G.f.: 4*x*(4 + 10*x - x^2 - 16*x^3) / ((1 - 2*x)^2*(1 + 2*x)^2).
a(n) = 8*a(n-2) - 16*a(n-4) for n>3.
(End)
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EXAMPLE
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Some solutions for n=4:
0 0 1 0 1 0 0 1 1 0 0 1 0 0 0 1 0 1 0 0
0 0 0 1 1 0 0 1 1 0 1 0 0 0 1 1 1 0 0 0
1 0 0 1 1 1 1 0 0 1 0 0 0 1 0 1 1 0 0 1
0 1 1 0 0 1 1 0 0 0 0 0 1 0 0 1 0 1 1 0
0 1 1 0 0 0 0 1 0 0 0 1 0 0 0 0 1 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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