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 A069164 #23 Mar 27 2022 03:21:55
%S A069164 1,2,12,20,24,28,36,40,44,52,56,68,72,76,80,88,92,104,116,124,136,148,
%T A069164 152,160,164,172,184,188,212,232,236,240,244,248,268,284,292,296,316,
%U A069164 328,332,344,356,376,388,404,412,424,428,432,436,452,472,480,488,508
%N A069164 Numbers k such that k*Sum_{d|k} 1/tau(d) is an integer.
%H A069164 Amiram Eldar, <a href="/A069164/b069164.txt">Table of n, a(n) for n = 1..10000</a>
%H A069164 Vaclav Kotesovec, <a href="/A069164/a069164.jpg">Plot of a(n)/(n*log(n)) for n = 2..100000</a>
%F A069164 Numbers k such that k*Sum_{d|k} 1/A000005(d) is an integer.
%t A069164 Select[Range[500], IntegerQ[# * DivisorSum[#, 1/DivisorSigma[0, #1] &]] &] (* _Amiram Eldar_, Feb 19 2021 *)
%o A069164 (PARI) isok(k) = denominator(k*sumdiv(k, d, 1/numdiv(d))) == 1; \\ _Michel Marcus_, Feb 15 2021
%Y A069164 Cf. A000005.
%K A069164 easy,nonn
%O A069164 1,2
%A A069164 _Benoit Cloitre_, Apr 09 2002