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

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

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