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Search: id:A070161
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| A070161 |
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Nonprime numbers n such that q=phi[n]/(sigma[n]-n-1) is integer and n is not a prime square. |
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+0
2
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| 15, 35, 95, 119, 143, 209, 287, 319, 323, 377, 527, 559, 779, 899, 903, 923, 989, 1007, 1189, 1199, 1343, 1349, 1763, 1919, 2159, 2507, 2759, 2911, 3239, 3599, 3827, 4031, 4607, 5183, 5207, 5249, 5459, 5543, 6439, 6887, 7067, 7279, 7739, 8159, 8639, 9179
(list; graph; listen)
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OFFSET
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1,1
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FORMULA
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q=A000010(n)/A048050(n) and n is not in A001248.
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EXAMPLE
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n=35:phi[35]=24, sigma[35]=1+5+7+35=48, chowla[35]=8, quotient=3
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MATHEMATICA
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Do[s=EulerPhi[n]/(DivisorSigma[1, n]-n-1); If[ !PrimeQ[n]&&!PrimeQ[Sqrt[n]]&&IntegerQ[s], Print[n]], {n, 2, 100000}]
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CROSSREFS
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Cf. A000010, A001065, A000203, A048050, A055940, A070159, A070160, A070037 A020492, A068418, A062972.
Sequence in context: A082663 A109068 A061367 this_sequence A142591 A074480 A037074
Adjacent sequences: A070158 A070159 A070160 this_sequence A070162 A070163 A070164
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Apr 26 2002
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