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A293711 Numbers n such that phi(sigma(n))/n < phi(sigma(m))/m for all m < n, where sigma is the sum of divisors function (A000203) and phi is Euler's totient function (A000010). 0
1, 3, 5, 11, 17, 23, 29, 59, 89, 149, 179, 239, 269, 359, 377, 389, 419, 839, 1049, 1259, 1889, 2099, 2309, 9239, 11549, 13859, 20789, 23099, 25409, 30029, 90089, 180179, 210209, 270269, 300299, 330329, 390389, 420419, 540539, 570569, 1017917, 1018013, 1021019 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..43.

MATHEMATICA

a={}; rm=2; Do[r=EulerPhi[DivisorSigma[1, n]]/n; If[r<rm, rm=r; AppendTo[a, n]], {n, 1, 100000}]; a

CROSSREFS

Cf. A000010, A000203, A062401.

Sequence in context: A248173 A244029 A106902 * A155938 A158318 A099596

Adjacent sequences:  A293708 A293709 A293710 * A293712 A293713 A293714

KEYWORD

nonn

AUTHOR

Amiram Eldar, Oct 15 2017

STATUS

approved

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Last modified October 17 11:59 EDT 2019. Contains 328110 sequences. (Running on oeis4.)