A073349 Numbers m such that sigma(m)/m is equal to sigma(k)/k for some k being superabundant (A004394).

1, 2, 4, 6, 12, 24, 28, 36, 48, 60, 120, 180, 234, 240, 360, 496, 600, 672, 720, 840, 1170, 1260, 1680, 1800, 2016, 2520, 4200, 5040, 8128, 10080, 12600, 15120, 22320, 25200, 27000, 27720, 37800, 55440, 55800, 55860, 110880, 138600, 166320, 167580, 277200

Offset: 1

Author

Benoit Cloitre, Aug 23 2002

Keywords

• nonn

Comments

Previous name was: Numbers n such that sigma(k)/k < sigma(n)/n for k=1,2,3...,n-1.

Links

• Amiram Eldar, Table of n, a(n) for n = 1..128

Crossrefs

Cf. A004394.

Programs

PARI

lista(nn) = {vs = Set(); maxs = 0; for(n = 1, nn, news = sigma(n, -1); if (news > maxs, maxs = news; print1(n, ", "); vs = Set(concat(vs, maxs));, if (setsearch(vs, news), print1(n, ", "));););} \\ Michel Marcus, Dec 02 2013

Extensions

New name and more terms from Michel Marcus, Dec 02 2013