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 A070807 #5 Oct 15 2013 22:31:19
%S A070807 4,6,8,9,10,12,14,15,16,18,20,21,24,26,28,30,32,34,35,36,39,40,42,45,
%T A070807 48,51,52,56,58,60,64,65,68,70,72,78,80,84,85,87,90,96,102,104,105,
%U A070807 112,116,119,120,128,130,136,140,144,145,153,156,160,168,170,174,180,192
%N A070807 Composite numbers n such that Cototient(totient(n))=A070556(n) is power of 2.
%e A070807 n=87=3.29:phi[87]=56,56-phi[56]=56-24=32
%t A070807 Do[s= EulerPhi[n]-EulerPhi[EulerPhi[n]]; If[IntegerQ[Log[2, s]]&&!PrimeQ[n], Print[n]], {n, 1, 10000000}]
%Y A070807 Cf. A070556, A051953, A054571, A070806, A070809-A070811.
%K A070807 nonn
%O A070807 1,1
%A A070807 _Labos Elemer_, May 08 2002