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 A164649 #7 Jul 14 2012 11:32:31 %S A164649 5797,10153,20377,50953,383719,405449,446039,486421,608399,973709, %T A164649 1321529,1521311,3086369,3228511,3451877,3529813,3859513,4552373, %U A164649 4767721,5827679,6194321,6479599,6724039,6927893,7038241,7919197,11696111,15893773,16894141,16924873 %N A164649 Numbers n such that sigma(n)/phi(n) = 36/25. %C A164649 A subsequence of A011257. See A164646-A164650 for related sequences. %H A164649 Donovan Johnson, <a href="/A164649/b164649.txt">Table of n, a(n) for n = 1..1000</a> %o A164649 (PARI) for( n=1,1e7, sigma(n)==36/25*eulerphi(n) && print1(n",")) %Y A164649 Cf. A000010 (=phi), A000203 (=sigma), A068390 (sigma/phi=4), A163667 (sigma/phi=9), A164646-A164650. %K A164649 nonn %O A164649 1,1 %A A164649 _M. F. Hasler_, Aug 22 2009 %E A164649 More terms from _Sean A. Irvine_, May 17 2010