%I #27 Oct 14 2023 15:28:39
%S 3,12,84,234,270,1080,1488,1638,6048,6552,24384,35640,199584,435708,
%T 2142720,4713984,12999168,18506880,36197280,100651008,208565280,
%U 240589440,275890944,299980800,470564640,3899750400,4138364160,6039429120,13286744064,17827568640
%N Numbers k such that A017666(k) = denominator(sigma(k)/k) = 3.
%C Numbers n such that sigma(n)/n = k + 1/3 with integer k are terms of this sequence (3, 12, 234, 1080, 6048, 6552, 435708, 4713984, ...).
%C Subsequence of A245774 (numbers n such that n divides 3*sigma(n)).
%C Union of A160320 (sigma(n)/n = k + 1/3) and A160321 (sigma(n)/n = k + 2/3). - _Michel Marcus_, Aug 27 2014
%H Jud McCranie, <a href="/A245775/b245775.txt">Table of n, a(n) for n = 1..44</a> (terms <= 10^13).
%e Number 12 is in sequence because A017666(12) = 3.
%o (Magma) [n: n in [1..3000000] | Denominator((SumOfDivisors(n))/n) eq 3]
%o (PARI) for(n=1,10^7,if(denominator(sigma(n)/n)==3,print1(n,", "))) \\ _Derek Orr_, Aug 26 2014
%Y Cf. A000203, A007691, A160320, A160321, A245774.
%K nonn
%O 1,1
%A _Jaroslav Krizek_, Aug 26 2014
%E More terms from A160320 and A160321 by _Michel Marcus_, Aug 27 2014