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 A072611 #17 May 23 2022 12:30:07
%S A072611 1,2,6,14,30,40,70,140,170,174,206,215,238,390,459,518,923,957,1334,
%T A072611 1364,1540,1634,2685,2974,4364,5180,5934,6048,6467,6510,6623,8028,
%U A072611 8094,8260,8814,12136,12954,14099,14841,15416,16472,17094,17835,17927,18873
%N A072611 Numbers k such that phi(k) divides sigma(k+1) - sigma(k).
%H A072611 Amiram Eldar, <a href="/A072611/b072611.txt">Table of n, a(n) for n = 1..1000</a>
%F A072611 Conjecture : Limit_{n -> infinity} log(a(n))/log(n) exists and = 2.6... .
%t A072611 Select[Range[20000],Divisible[DivisorSigma[1,#+1]-DivisorSigma[1,#], EulerPhi[#]]&] (* _Harvey P. Dale_, Sep 15 2011 *)
%Y A072611 Cf. A000010, A053222.
%K A072611 nonn
%O A072611 1,2
%A A072611 _Benoit Cloitre_, Aug 07 2002