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A064376 Numbers n such that sigma_3(n) > phi(n)^4. 1

%I

%S 2,3,4,6,8,10,12,14,16,18,20,22,24,28,30,36,40,42,48,54,60,66,70,72,

%T 78,84,90,102,114,120,126,132,150,168,180,210,330,420

%N Numbers n such that sigma_3(n) > phi(n)^4.

%C This sequence is finite, since by Grönwall's theorem sigma_3(n) <= sigma(n)^3 << (n log log n)^3 but phi(n)^4 >> (n/log log n)^4. - _Charles R Greathouse IV_, Nov 19 2015

%F Solutions to A001158(n) > phi(n)^4.

%o (PARI) is(n)=my(f=factor(n)); sigma(f, 3)>eulerphi(f)^4 \\ _Charles R Greathouse IV_, Nov 19 2015

%Y Cf. A001158, A000010.

%K nonn,fini

%O 1,1

%A _Labos Elemer_, Sep 27 2001

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Last modified September 21 17:46 EDT 2019. Contains 327273 sequences. (Running on oeis4.)