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A137243
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Number of coprime pairs (a,b) with -n <= a,b <= n.
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0
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8, 16, 32, 48, 80, 96, 144, 176, 224, 256, 336, 368, 464, 512, 576, 640, 768, 816, 960, 1024, 1120, 1200, 1376, 1440, 1600, 1696, 1840, 1936, 2160, 2224, 2464, 2592, 2752, 2880, 3072, 3168, 3456, 3600, 3792, 3920, 4240, 4336, 4672, 4832, 5024, 5200, 5568
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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EXAMPLE
| a(1)=8 because there are eight coprime pairs (1,1), (1,0), (1,-1), (0,1), (0,-1), (-1,1),(-1,0),(-1,-1) with integral entries of absolute value <= 1. In the same way a(2)=16 as there are sixteen coprime pairs (2,1), (2,-1), (1,2), (1,1), (1,0), (1,-1),(1,-2), (0,1), (0,-1), (-1,2), (-1,1), (-1,0), (-1,-1), (-1,-2), (-2,1), (-2,-1) of integral entries of absolute value <= 2.
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CROSSREFS
| Sequence in context: A020948 A106841 A139598 * A068935 A054743 A192135
Adjacent sequences: A137240 A137241 A137242 * A137244 A137245 A137246
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KEYWORD
| nonn
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AUTHOR
| Kilian Kilger (kilian(AT)mathi.uni-heidelberg.de), May 11 2008
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