%I #9 Aug 31 2017 23:18:03

%S 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 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 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 Number of iterations of f(x) = phi(x)+1 on n required to reach a prime.

%H T. D. Noe, <a href="/A039651/b039651.txt">Table of n, a(n) for n = 1..1000</a>

%t Table[Length[NestWhileList[EulerPhi[#] + 1 &, n, UnsameQ, All]] - 2, {n, 100}] (* _T. D. Noe_, Oct 17 2013 *)

%Y Cf. A039649, A039650, A039651, A039652, A039653, A039654, A039655, A039656.

%K nonn

%O 1,15

%A _David W. Wilson_