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A055681
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Numbers n such that n | Sigma(n)-Phi(n).
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1
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1, 2, 12, 42, 1242, 75960, 1447488, 3506976, 6137440, 10834488, 17156160, 90288000, 431440416, 454460160, 704592000
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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MATHEMATICA
| Do[If[Mod[DivisorSigma[1, n]-EulerPhi[n], n]==0, Print[n]], {n, 1, 10^9}]
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CROSSREFS
| Cf. A011774, A000203, A000010, A054024, A056075.
Sequence in context: A094702 A001621 A189491 * A111389 A203278 A013704
Adjacent sequences: A055678 A055679 A055680 * A055682 A055683 A055684
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KEYWORD
| nonn
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AUTHOR
| Robert G. Wilson v (rgwv(AT)rgwv.com), Jun 09 2000
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