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A245775
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Numbers k such that A017666(k) = denominator(sigma(k)/k) = 3.
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8
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3, 12, 84, 234, 270, 1080, 1488, 1638, 6048, 6552, 24384, 35640, 199584, 435708, 2142720, 4713984, 12999168, 18506880, 36197280, 100651008, 208565280, 240589440, 275890944, 299980800, 470564640, 3899750400, 4138364160, 6039429120, 13286744064, 17827568640
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OFFSET
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1,1
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COMMENTS
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Numbers n such that sigma(n)/n = k + 1/3 with integer k are terms of this sequence (3, 12, 234, 1080, 6048, 6552, 435708, 4713984, ...).
Subsequence of A245774 (numbers n such that n divides 3*sigma(n)).
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LINKS
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EXAMPLE
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Number 12 is in sequence because A017666(12) = 3.
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PROG
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(Magma) [n: n in [1..3000000] | Denominator((SumOfDivisors(n))/n) eq 3]
(PARI) for(n=1, 10^7, if(denominator(sigma(n)/n)==3, print1(n, ", "))) \\ Derek Orr, Aug 26 2014
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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