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 A288162 #39 Mar 08 2024 11:59:50
%S A288162 26,52,104,208,338,416,676,832,1352,1664,2704,3328,4394,5408,6656,
%T A288162 8788,10816,13312,17576,21632,26624,35152,43264,53248,57122,70304,
%U A288162 86528,106496,114244,140608,173056,212992,228488,281216,346112,425984,456976,562432,692224,742586,851968,913952
%N A288162 Numbers whose prime factors are 2 and 13.
%C A288162 Numbers k such that phi(k)/k = 6/13.
%H A288162 Charles R Greathouse IV, <a href="/A288162/b288162.txt">Table of n, a(n) for n = 1..10000</a>
%F A288162 a(n) = 26 * A107326(n). - _David A. Corneth_, Jun 06 2017
%F A288162 Sum_{n>=1} 1/a(n) = 1/12. - _Amiram Eldar_, Dec 22 2020
%t A288162 Select[Range[920000],FactorInteger[#][[All,1]]=={2,13}&] (* _Harvey P. Dale_, Jun 18 2021 *)
%o A288162 (PARI) is(n) = factor(n)[, 1]~==[2, 13] \\ _Felix Fröhlich_, Jun 06 2017
%o A288162 (PARI) list(lim)=my(v=List(),t); for(n=1,logint(lim\2,13), t=13^n; while((t<<=1)<=lim, listput(v,t))); Set(v) \\ _Charles R Greathouse IV_, Jun 11 2017
%o A288162 (Magma) [n:n in [1..100000] | Set(PrimeDivisors(n)) eq {2,13}]; // _Marius A. Burtea_, May 10 2019
%Y A288162 Cf. A033845, A033846, A033847, A033848, A033849, A033850, A033851, A086780, A107326, A143207.
%K A288162 nonn
%O A288162 1,1
%A A288162 _Bernard Schott_, Jun 06 2017