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A023198
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Numbers n such that sigma(n) >= 4n.
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3
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27720, 30240, 32760, 50400, 55440, 60480, 65520, 75600, 83160, 85680, 90720, 95760, 98280, 100800, 105840, 110880, 115920, 120120, 120960, 128520, 131040, 138600, 141120, 143640, 151200, 163800, 166320, 171360, 176400, 180180, 181440, 184800
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Called 4-abundant numbers. The first odd number is A119240(4) = 1853070540093840001956842537745897243375. - 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..1000
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MATHEMATICA
| Select[Range[1000000], DivisorSigma[1, #] >= 4*#&] [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Apr 21 2010]
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CROSSREFS
| Sequence in context: A101214 A202589 A079321 * A204831 A190111 A068404
Adjacent sequences: A023195 A023196 A023197 * A023199 A023200 A023201
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KEYWORD
| nonn
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AUTHOR
| David W. Wilson (davidwwilson(AT)comcast.net)
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