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A023198 Numbers n such that sigma(n) >= 4n. 6

%I

%S 27720,30240,32760,50400,55440,60480,65520,75600,83160,85680,90720,

%T 95760,98280,100800,105840,110880,115920,120120,120960,128520,131040,

%U 138600,141120,143640,151200,163800,166320,171360,176400,180180,181440,184800

%N Numbers n such that sigma(n) >= 4n.

%C Called 4-abundant numbers. The first odd number is A119240(4) = 1853070540093840001956842537745897243375. - _T. D. Noe_, Mar 31 2011

%D Melvyn B. Nathanson, Elementary Methods in Number Theory, Springer, 2000, p 260.

%H T. D. Noe, <a href="/A023198/b023198.txt">Table of n, a(n) for n = 1..1000</a>

%t Select[Range[1000000], DivisorSigma[1, #] >= 4*#&] (* _Vladimir Joseph Stephan Orlovsky_, Apr 21 2010 *)

%K nonn

%O 1,1

%A _David W. Wilson_

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Last modified October 14 03:58 EDT 2019. Contains 327995 sequences. (Running on oeis4.)