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Search: id:A055681
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| A055681 |
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Numbers n such that n | Sigma(n)-Phi(n). |
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+0
2
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| 1, 2, 12, 42, 1242, 75960, 1447488, 3506976, 6137440, 10834488, 17156160, 90288000, 431440416, 454460160, 704592000
(list; graph; listen)
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OFFSET
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1,2
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MATHEMATICA
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Do[If[Mod[DivisorSigma[1, n]-EulerPhi[n], n]==0, Print[n]], {n, 1, 10^9}]
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CROSSREFS
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Cf. A011774, A000203, A000010, A540024, A056075.
Sequence in context: A048014 A094702 A001621 this_sequence A111389 A013704 A025495
Adjacent sequences: A055678 A055679 A055680 this_sequence A055682 A055683 A055684
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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), Jun 09 2000
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