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%I #13 Jul 10 2015 23:01:31
%S 1,2,3,4,6,8,9,10,12,15,16,18,20,24,30,36,40,42,48,60,72,80,84,90,96,
%T 120,126,144,168,180,210,240,252,280,288,300,360,420,432,480,504,540,
%U 560,600,630,720,840,900,1008,1080,1260
%N Sigma-crowded numbers: n such that d(n)/sigma(n) is larger than d(m)/sigma(m) for all m > n.
%C Since d(m) < 2*sqrt(m) < 2*sigma(m), we need only test values of m < (2*sigma(n)/d(n))^2.
%H Donovan Johnson, <a href="/A067023/b067023.txt">Table of n, a(n) for n = 1..300</a>
%t crowded[n_] := Module[{}, stop=(2/(dovern=DivisorSigma[0, n]/DivisorSigma[1, n]))^2; For[m=n+1, m<stop, m++, If[DivisorSigma[0, m]/DivisorSigma[1, m] >=dovern, Return[False]]]; True]; Select[Range[1, 13000], crowded]
%Y An analog of A066523. Cf. A002182, A000005, A000203, A004394, A034884, A056758.
%K nonn
%O 1,2
%A _Labos Elemer_, Jan 09 2002
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