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 A333633 #29 Apr 12 2020 03:52:38
%S A333633 1,5,24,22,21,40,48,136,110,90,88,656,102,80,96,68,55,464,65,117,91,
%T A333633 116,85,272,95,148,133,164,115,160,147,333,247,212,145,243968,155,244,
%U A333633 217,405,230,11072,185,292,259,1184,205,237824,215,657,301,356,189,343,329,388,559,404
%N A333633 Smallest m such that sigma(m) == 2*n (mod phi(m)) or 0 if no solution exists.
%C A333633 a(221) <= 288230257234804736 = 2^(k-2)*(2^k-443) for k=30. - _Michel Marcus_, Apr 02 2020
%C A333633 a(221) > 10^13. - _Giovanni Resta_, Apr 12 2020
%H A333633 Michel Marcus, <a href="/A333633/b333633.txt">Table of n, a(n) for n = 0..220</a>
%o A333633 (PARI) g(n) = my(f=factor(n)); sigma(f) % eulerphi(f);
%o A333633 a(n) = {n *= 2; my(k=1); while (g(k) != n, k++); k;} \\ _Michel Marcus_, Mar 30 2020
%Y A333633 Bisection of A072808.
%Y A333633 Cf. A000203, A000010, A063514, A067192, A067193.
%K A333633 nonn
%O A333633 0,2
%A A333633 _Michel Marcus_, Mar 30 2020
%E A333633 a(0) prepended by _Jinyuan Wang_, Mar 30 2020