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 A054740 #8 Dec 19 2015 23:43:12 %S A054740 0,1,1,2,1,2,1,2,2,1,2,2,2,1,2,2,2,1,2,2,2,2,1,2,2,2,2,2,1,2,2,2,2,2, %T A054740 1,2,2,2,2,2,2,1,2,2,2,2,2,2,1,2,2,2,2,2,2,2,1,2,2,2,2,2,2,2,2,1,2,2, %U A054740 2,2,2,2,2,2,1,2,2,2,2,2,2,2,2,2,1,2,2,2,2,2,2,2,2,2,2,1,2,2,2,2,2,2,2,2,2 %N A054740 Cototient(n)/totient(n) when this is an integer. %C A054740 EulerPhi of x divides x (A007694) if and only if EulerPhi divides x-EulerPhi. This quotient is smaller by 1 than A049237. %D A054740 Sárközy A. and Suranyi J., Number Theory Problem Book (in Hungarian) %F A054740 A051953[A007694(n)]/A000010[A007694(n)] = A049237(n)-1 %e A054740 x=2592, Phi[2592]=864, Cototient[x]=2592-864=1728 and the quotients are as follows: x/Phi=2592/864=3 or Cototient[x]/Phi[x]=1728/864=2; x always has a form of 2^u*3^w %t A054740 Select[(#-EulerPhi[#])/EulerPhi[#]&/@Range[300000],IntegerQ] (* _Harvey P. Dale_, Mar 01 2015 *) %Y A054740 A000010, A049237, A007694, A051953. %K A054740 nonn %O A054740 1,4 %A A054740 _Labos Elemer_, Apr 26 2000