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 A067382 #12 Jun 24 2014 01:08:20 %S A067382 13,71,89,203,305,319,667,1363,1421,1525,1711,1889,2407,2933,3103, %T A067382 4609,4615,4843,5191,6583,7123,7625,7627,9947,10063,10411,11107,13543, %U A067382 13891,14587,16327,17023,19693,20851,23075,24331,24721,25027,25723 %N A067382 Numbers n such that sigma(phi(n))/sigma(n) = 2. %C A067382 Sequence is infinite. Contains subsequences like 5^i*61, 5^i*13*71, 7^i*29 ... (see also Farideh Firoozbakht's comment on A033631.) - vim(AT)gmx.li, Nov 03 2006 %H A067382 Donovan Johnson, <a href="/A067382/b067382.txt">Table of n, a(n) for n = 1..1000</a> %t A067382 For[ n=1, True, n++, If[ DivisorSigma[ 1, EulerPhi[ n ] ]/DivisorSigma[ 1, n ]==2, Print[ n ] ] ] %o A067382 (PARI) is(n)=sigma(eulerphi(n=factor(n)))/sigma(n)==2 \\ _Charles R Greathouse IV_, Nov 27 2013 %Y A067382 Cf. A033631, A066831, A067383, A067384, A067385, A197952. %K A067382 nonn %O A067382 1,1 %A A067382 _Dean Hickerson_, Jan 20 2002