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 A227307 #17 Dec 31 2024 06:33:42
%S A227307 2,6,15,19,207,958,1335,1365,1635,2686,2975,3201,4365,4536,8586,14842,
%T A227307 16120,18874,19359,20146,24958,33999,36567,42819,53580,56565,64666,
%U A227307 74919,79827,79834,84135,92686,109215,111507,116938,122074,138238,147455,161002,162603,166935
%N A227307 Numbers k that divide sigma(k) - sigma(k-1).
%H A227307 Amiram Eldar, <a href="/A227307/b227307.txt">Table of n, a(n) for n = 1..1000</a>
%t A227307 With[{m = 200000}, 1 + Position[Differences[DivisorSigma[1, Range[m]]]/Range[2, m], _?IntegerQ] // Flatten] (* _Amiram Eldar_, Dec 31 2024 *)
%o A227307 (PARI) list(lim) = {my(s1 = 1, s2); for(k = 2, lim, s2 = sigma(k); if(!((s2-s1) % k), print1(k, ", ")); s1 = s2);} \\ _Amiram Eldar_, Dec 31 2024
%Y A227307 Cf. A000203, A053222, A223136, A223137, A227306.
%Y A227307 A231546 is a subsequence.
%K A227307 nonn
%O A227307 1,1
%A A227307 _Alex Ratushnyak_, Jul 05 2013