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 A293992 #13 Jul 18 2021 01:54:40
%S A293992 8,115,187,1375,2455,8143,13543,18261,21103,23479,40615,41623,43279,
%T A293992 49183,49441,51703,56743,61063,61279,61423,89287,95551,137887,214303,
%U A293992 331567,379807,476071,715471,1422871,1515967,1793527,1977127,2431087,3098527,3663871
%N A293992 Numbers k such that sigma(k) - k - 1 is a perfect number.
%e A293992 sigma(8) - 8 - 1 = 6, a perfect number, so 8 is a term;
%e A293992 sigma(115) - 115 - 1 = 28, a perfect number, so 115 is a term.
%t A293992 With[{pn=PerfectNumber[Range[10]]},Select[Range[37*10^5],MemberQ[pn, DivisorSigma[ 1,#]-#-1]&]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Feb 04 2019 *)
%Y A293992 Cf. A000396, A048050.
%K A293992 nonn
%O A293992 1,1
%A A293992 _Zdenek Cervenka_, Oct 21 2017