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 A039651 #9 Aug 31 2017 23:18:03
%S A039651 1,0,0,1,0,1,0,1,1,1,0,1,0,1,2,2,0,1,0,2,1,1,0,2,2,1,1,1,0,2,0,1,2,1,
%T A039651 3,1,0,1,3,1,0,1,0,2,3,1,0,1,1,2,3,3,0,1,1,3,1,1,0,1,0,1,1,3,2,2,0,3,
%U A039651 4,3,0,3,0,1,1,1,1,3,0,3,2,1,0,3,3,1,2,1,0,3,1,4,1,1,1,3,0,1,1,1,0,3,0,2,2
%N A039651 Number of iterations of f(x) = phi(x)+1 on n required to reach a prime.
%H A039651 T. D. Noe, <a href="/A039651/b039651.txt">Table of n, a(n) for n = 1..1000</a>
%t A039651 Table[Length[NestWhileList[EulerPhi[#] + 1 &, n, UnsameQ, All]] - 2, {n, 100}] (* _T. D. Noe_, Oct 17 2013 *)
%Y A039651 Cf. A039649, A039650, A039651, A039652, A039653, A039654, A039655, A039656.
%K A039651 nonn
%O A039651 1,15
%A A039651 _David W. Wilson_