%I #9 Mar 28 2013 05:57:46
%S 11264,14175,28160,44100,46464,51200,95744,96000,107008,109375,109760,
%T 116160,129536,151263,162624,163328,174592,192000,208384,224000,
%U 230912,239360,242176,242550,246960,264704,267520,281600,286650,298496,302016,323840,332288
%N Numbers n such that n = k/d(k) has exactly 4 solutions, where d(k) = number of divisors of k.
%H Donovan Johnson, <a href="/A217125/b217125.txt">Table of n, a(n) for n = 1..1000</a>
%e k/d(k) = 11264 for exactly 4 k values: 360448, 585728, 630784 and 1115136.
%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[350000], cnt[#] == 4 &] (* _Jean-François Alcover_, Sep 28 2012 *)
%Y Cf. A051278, A051279, A051280, A051346, A217126, A217127.
%K nonn
%O 1,1
%A _Donovan Johnson_, Sep 27 2012