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A077006 Numbers n such that sigma(n)/n >= sigma(m)/m for all m <= n. 3
1, 2, 4, 6, 12, 24, 36, 48, 60, 120, 180, 240, 360, 720, 840, 1260, 1680, 2520, 5040, 10080, 15120, 25200, 27720, 55440, 110880, 166320, 277200, 332640, 360360, 554400 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..30.

EXAMPLE

360360 is included in this sequence (but not in A004394) because its abundancy (sigma(n)/n = 48/11) is the same as that of the previous record holder (namely 332640). [From Gerard P. Michon, May 20 2009]

MATHEMATICA

abund[n_] := abund[n] = DivisorSigma[1, n]/n; ok[n_] := (r = True; m = 1; While[m <= n, If[abund[n] < abund[m], r = False; Break[]]; m++]; r); n = 1; A077006 = {}; While[n < 10^6, If[ok[n], Print[n]; AppendTo[ A077006, n]]; n++]; A077006 (* Jean-Fran├žois Alcover, Dec 12 2011 *)

CROSSREFS

Almost same as A004394.

Sequence in context: A242298 A189686 A002182 * A166981 A004394 A137425

Adjacent sequences:  A077003 A077004 A077005 * A077007 A077008 A077009

KEYWORD

nice,nonn,more

AUTHOR

Mike Speciner, Oct 15 2003

STATUS

approved

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Last modified July 25 12:29 EDT 2017. Contains 289795 sequences.