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Search: id:A060664
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| A060664 |
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Sigma(x) = n has exactly eight solutions. |
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1
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| 336, 432, 672, 756, 840, 1536, 1620, 1764, 1848, 2280, 2394, 2604, 2808, 3264, 4080, 4480, 4860, 5328, 6528, 6624, 7128, 8316, 8568, 8880, 10608, 11040, 11448, 12288, 12420, 12636, 13176, 13200, 13248, 13536, 13860, 14196, 14208, 14448, 14700
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OFFSET
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1,1
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EXAMPLE
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336 = sigma(132) = sigma(140) = sigma(182) = sigma(188) = sigma(195) = sigma(249) = sigma(287) = sigma(299).
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MATHEMATICA
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a = Table[ 0, {20000} ]; Do[ s = DivisorSigma[ 1, n ]; If[ s < 20001, a[ [ s ] ]++ ], {n, 1, 20000} ]; Select[ Range[ 20000 ], a[ [ # ] ] == 8 & ]
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CROSSREFS
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Cf. A007370, A007371, A007372.
Adjacent sequences: A060661 A060662 A060663 this_sequence A060665 A060666 A060667
Sequence in context: A038648 A137522 A090487 this_sequence A064259 A006909 A067708
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KEYWORD
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nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Apr 18 2001
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