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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
OFFSET
1,1
LINKS
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}]
KEYWORD
nonn
AUTHOR
Labos Elemer, Apr 26 2002
STATUS
approved