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A023197
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Numbers n such that sigma(n) >= 3n.
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5
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120, 180, 240, 360, 420, 480, 504, 540, 600, 660, 672, 720, 780, 840, 900, 960, 1008, 1080, 1200, 1260, 1320, 1344, 1440, 1512, 1560, 1584, 1620, 1680, 1800, 1848, 1872, 1890, 1920, 1980, 2016, 2040, 2100, 2160, 2184, 2280, 2340, 2352, 2376, 2400, 2520
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Called 3-abundant numbers. The first odd number is A119240(3) = 1018976683725. - T. D. Noe, Mar 31 2011
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REFERENCES
| Melvyn B. Nathanson, Elementary Methods in Number Theory, Springer, 2000, p 260.
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LINKS
| T. D. Noe, Table of n, a(n) for n = 1..10000
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MATHEMATICA
| Select[Range[10000], DivisorSigma[1, #] >= 3*#&] [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Apr 21 2010]
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CROSSREFS
| Sequence in context: A030634 A189975 A090782 * A204828 A204830 A054572
Adjacent sequences: A023194 A023195 A023196 * A023198 A023199 A023200
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KEYWORD
| nonn
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AUTHOR
| David W. Wilson (davidwwilson(AT)comcast.net)
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