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 A066673 #12 Oct 15 2013 22:31:15
%S A066673 7,13,35,65,97,193,485,769,1649,3281,8245,12289,24929,49601,124645,
%T A066673 197633,423793,786433,2118965,3158273,6357089,12648641,31785445,
%U A066673 50397953,108070513,202113281,540352565,805384193,1633771873,3221225473,8168859365,12952273921
%N A066673 Smallest term x from A066669 such that phi(x) = 2^n times some prime.
%e A066673 Phi of {7, 13, 35, 65, 97, 193, 485, 769} is {6, 12, 24, 48, 96, 192, 384, 768}, of which {2, 4, 8, 16, 32, 64, 128, 256} are the largest even factors.
%Y A066673 Cf. A000010, A066669-A066672.
%K A066673 nonn
%O A066673 1,1
%A A066673 _Labos Elemer_, Dec 18 2001
%E A066673 a(9)-a(30) from _Donovan Johnson_, May 23 2011
%E A066673 a(31)-a(32) from _Donovan Johnson_, May 26 2013