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 A067081 #34 May 13 2025 23:59:28
%S A067081 5,125,1253,1673,3127,5191,7615,12035,43817,47795,48559,49955,56975,
%T A067081 58373,61721,63545,68033,78395,97411,106001,108473,109939,111451,
%U A067081 111683,123497,123797,131659,137081,192065,192279,224561,228377,274273,280313,290417,290719,351815
%N A067081 Numbers k such that sigma(k+1) = 2*sigma(k).
%C A067081 Sequence seems to consist only of odd values.
%H A067081 Amiram Eldar, <a href="/A067081/b067081.txt">Table of n, a(n) for n = 1..2500</a> (terms 1..761 from Harry J. Smith)
%t A067081 f[n_]:=DivisorSigma[1,n]; lst={};Do[If[2*f[n]==f[n+1],AppendTo[lst,n]],{n,9!}];lst (* _Vladimir Joseph Stephan Orlovsky_, Jul 22 2009 *)
%t A067081 Position[Partition[DivisorSigma[1,Range[300000]],2,1],_?(2#[[1]]==#[[2]]&),1,Heads->False]//Flatten (* _Harvey P. Dale_, Oct 21 2024 *)
%o A067081 (PARI) isok(k) = { sigma(k+1) == 2*sigma(k) } \\ _Harry J. Smith_, May 08 2010
%Y A067081 Cf. A000203 (sigma).
%K A067081 nonn
%O A067081 1,1
%A A067081 _Benoit Cloitre_, Feb 18 2002
%E A067081 More terms from _Harry J. Smith_, May 08 2010