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A064376 Numbers n such that sigma_3(n) > phi(n)^4. 1
2, 3, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 28, 30, 36, 40, 42, 48, 54, 60, 66, 70, 72, 78, 84, 90, 102, 114, 120, 126, 132, 150, 168, 180, 210, 330, 420 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

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

LINKS

Table of n, a(n) for n=1..38.

FORMULA

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

PROG

(PARI) is(n)=my(f=factor(n)); sigma(f, 3)>eulerphi(f)^4 \\ Charles R Greathouse IV, Nov 19 2015

CROSSREFS

Cf. A001158, A000010.

Sequence in context: A045718 A068005 A055721 * A283808 A068578 A203812

Adjacent sequences:  A064373 A064374 A064375 * A064377 A064378 A064379

KEYWORD

nonn,fini

AUTHOR

Labos Elemer, Sep 27 2001

STATUS

approved

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Last modified August 25 14:35 EDT 2019. Contains 326324 sequences. (Running on oeis4.)