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%I #19 Feb 18 2021 03:02:45
%S 11264,14175,28160,44100,46464,51200,64000,82944,95744,96000,107008,
%T 109375,109760,116160,129536,151263,162624,163328,174592,192000,
%U 208384,224000,230912,239360,242176,242550,246960,264704,267520,281600,286650,290304,298496,302016
%N Numbers that can be written as k/d(k) in four or more ways, where d(k) = number of divisors of k.
%H Donovan Johnson, <a href="/A051346/b051346.txt">Table of n, a(n) for n = 1..1000</a>
%e From _Jon E. Schoenfield_, Feb 18 2021: (Start)
%e 11264 is a term because it can be written as k/d(k) in four ways:
%e k = 360448: 360448/d(360448) = 360448/32 = 11264;
%e k = 585728: 585728/d(585728) = 585728/52 = 11264;
%e k = 630784: 630784/d(630784) = 630784/56 = 11264;
%e k = 1115136: 1115136/d(1115136) = 1115136/99 = 11264. (End)
%t (* Assuming 3*10^5 <= k <= 3*10^8 *) ClearAll[cnt]; cnt[_] = 0; Do[ If[IntegerQ[n = k/DivisorSigma[0, k]], cnt[n]++; If[cnt[n] >= 4, Print[{n, k, cnt[n]}]]], {k, 3*10^5, 3*10^8}]; Select[Range[310000], cnt[#] >= 4 &] (* _Jean-François Alcover_, Sep 28 2012 *)
%Y Cf. A000005, A051278, A051279, A051280, A217125, A217126, A217127.
%K nonn
%O 1,1
%A _David W. Wilson_
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