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A070161 Nonprime numbers n such that q=phi(n)/(sigma(n)-n-1) is an integer and n is not a prime square. 3
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; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Donovan Johnson, Table of n, a(n) for n = 1..10000

FORMULA

q=A000010(n)/A048050(n) and n is not in A001248.

EXAMPLE

n=35: phi(35)=24, sigma(35)=1+5+7+35=48, chowla(35)=12, quotient=2

MATHEMATICA

Do[s=EulerPhi[n]/(DivisorSigma[1, n]-n-1); If[ !PrimeQ[n]&&!PrimeQ[Sqrt[n]]&&IntegerQ[s], Print[n]], {n, 2, 100000}]

CROSSREFS

Cf. A000010, A001065, A000203, A048050, A055940, A070159, A070160, A070037 A020492, A068418, A062972.

Sequence in context: A109068 A238232 A061367 * A142591 A074480 A194580

Adjacent sequences:  A070158 A070159 A070160 * A070162 A070163 A070164

KEYWORD

nonn

AUTHOR

Labos Elemer, Apr 26 2002

STATUS

approved

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Last modified October 25 06:26 EDT 2014. Contains 248518 sequences.