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 A066994 #24 Apr 27 2025 02:46:30
%S A066994 1,2,3,4,6,8,10,12,14,15,16,18,20,21,24,26,27,30,32,35,36,39,40,42,48,
%T A066994 54,55,56,60,63,64,70,72,78,80,84,88,96,98,104,105,108,110,114,116,
%U A066994 120,125,126,128,135,140,144,147,150,155,156,160,162,165,168,189,190,192
%N A066994 Numbers k such that phi(k) divides k*sigma(k).
%H A066994 Amiram Eldar, <a href="/A066994/b066994.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..1000 from Harry J. Smith)
%t A066994 Select[Range[200],Divisible[# DivisorSigma[1,#],EulerPhi[#]]&] (* _Harvey P. Dale_, Aug 23 2019 *)
%o A066994 (PARI) isok(k) = { (k*sigma(k)) % eulerphi(k) == 0 } \\ _Harry J. Smith_, Apr 23 2010
%Y A066994 Cf. A000010 (phi), A000203 (sigma), A011775.
%Y A066994 Subsequences: A007694, A020492.
%K A066994 nonn
%O A066994 1,2
%A A066994 _Benoit Cloitre_, Jan 27 2002
%E A066994 Missing term a(7)=10 added by _Harry J. Smith_, Apr 23 2010