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 A067384 #11 Jun 24 2014 01:08:21 %S A067384 121679,1043909,2350171,2918263,3396103,3566807,3688067,4019467, %T A067384 4562827,5963407,7300697,7485979,7853933,8103301,8364151,9237779, %U A067384 9514213,9638527,10531123,11094619,11384447,12721937,13576267 %N A067384 Numbers n such that sigma(phi(n))/sigma(n) = 4. %C A067384 Subsequence of A066881. - _R. J. Mathar_, Sep 30 2008 %H A067384 Donovan Johnson, <a href="/A067384/b067384.txt">Table of n, a(n) for n = 1..500</a> %t A067384 For[ n=1, True, n++, If[ DivisorSigma[ 1, EulerPhi[ n ] ]/DivisorSigma[ 1, n ]==4, Print[ n ] ] ] %o A067384 (PARI) is(n)=sigma(phi(n=factor(n)))/sigma(n)==4 \\ _Charles R Greathouse IV_, Nov 27 2013 %Y A067384 Cf. A033631, A066831, A067382, A067383, A067385, A197952. %K A067384 nonn %O A067384 1,1 %A A067384 _Dean Hickerson_, Jan 20 2002