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 A090552 #12 Mar 21 2020 10:41:04
%S A090552 1,2,5,6,11,14,15,23,30,46,51,55,66,70,94,115,119,138,154,165,210,282,
%T A090552 310,322,345,357,382,385,462,658,682,705,759,766,805,930,966,1146,
%U A090552 1155,1270,1426,1491,1551,1581,1645,1705,1771,1915,1974,2046,2170,2298,2415
%N A090552 a(1)=1; for n>1, a(n) is the smallest positive integer for which sigma(a(n)) is a multiple of sigma(a(n-1)).
%H A090552 Harvey P. Dale, <a href="/A090552/b090552.txt">Table of n, a(n) for n = 1..61</a>
%e A090552 After a(4)=6, with sigma(6)=12, the smallest number k such that sigma(k) is a multiple of 12 is 11, with sigma(11)=12. Thus a(5)=11.
%t A090552 msa[n_]:=Module[{s1=DivisorSigma[1,n],n2=n+1},While[Mod[DivisorSigma[1,n2],s1]!=0,n2++];n2]; NestList[msa,1,60] (* _Harvey P. Dale_, Mar 20 2020 *)
%o A090552 (PARI) lista(nn) = {a = 1; print1(a, ", "); for (n = 1, nn, sa = sigma(a); a++; while (sigma(a) % sa, a++); print1(a, ", "););} \\ _Michel Marcus_, Oct 12 2013
%Y A090552 Cf. A090553.
%K A090552 nonn
%O A090552 1,2
%A A090552 _Amarnath Murthy_, Dec 09 2003
%E A090552 Corrected, extended and edited by _John W. Layman_, Aug 10 2004