This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A245775 #27 Oct 14 2023 15:28:39 %S A245775 3,12,84,234,270,1080,1488,1638,6048,6552,24384,35640,199584,435708, %T A245775 2142720,4713984,12999168,18506880,36197280,100651008,208565280, %U A245775 240589440,275890944,299980800,470564640,3899750400,4138364160,6039429120,13286744064,17827568640 %N A245775 Numbers k such that A017666(k) = denominator(sigma(k)/k) = 3. %C A245775 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 A245775 Subsequence of A245774 (numbers n such that n divides 3*sigma(n)). %C A245775 Union of A160320 (sigma(n)/n = k + 1/3) and A160321 (sigma(n)/n = k + 2/3). - _Michel Marcus_, Aug 27 2014 %H A245775 Jud McCranie, <a href="/A245775/b245775.txt">Table of n, a(n) for n = 1..44</a> (terms <= 10^13). %e A245775 Number 12 is in sequence because A017666(12) = 3. %o A245775 (Magma) [n: n in [1..3000000] | Denominator((SumOfDivisors(n))/n) eq 3] %o A245775 (PARI) for(n=1,10^7,if(denominator(sigma(n)/n)==3,print1(n,", "))) \\ _Derek Orr_, Aug 26 2014 %Y A245775 Cf. A000203, A007691, A160320, A160321, A245774. %K A245775 nonn %O A245775 1,1 %A A245775 _Jaroslav Krizek_, Aug 26 2014 %E A245775 More terms from A160320 and A160321 by _Michel Marcus_, Aug 27 2014