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A087485
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Odd numbers n such that 2n-sigma(n)=6.
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5
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OFFSET
| 1,1
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COMMENTS
| This is a subsequence of A077374. There are no others up to 2*10^9. Except for the first term all known terms of this sequence are divisible by 15. Is there a number n > 1 such that gcd(a(n),3)=1 or gcd(a(n),5)=1?
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EXAMPLE
| 15 is in the sequence because 2*15-sigma(15)=6.
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MATHEMATICA
| Do[If[OddQ[n]&&2n-DivisorSigma[1, n]==6, Print[n]], {n, 2*10^9}]
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CROSSREFS
| Cf. A077374, A087167, A088011, A088012.
Sequence in context: A042725 A041096 A007541 * A156377 A069526 A061039
Adjacent sequences: A087482 A087483 A087484 * A087486 A087487 A087488
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KEYWORD
| hard,more,nonn
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AUTHOR
| Farideh Firoozbakht (f.firoozbakht(AT)sci.ui.ac.ir), Oct 23 2003
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