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 A053475 #30 Jun 09 2018 06:16:59
%S A053475 2,3,3,4,3,5,3,5,4,6,3,6,3,6,4,6,3,7,3,7,5,7,3,7,4,7,5,7,3,8,3,7,4,8,
%T A053475 4,8,3,8,5,8,3,9,3,8,6,8,3,8,4,9,4,8,3,9,5,8,6,9,3,9,3,8,6,8,4,9,3,9,
%U A053475 5,9,3,9,3,9,5,9,4,10,3,9,6,10,3,10,6,9,4,9,3,10,4,9,5,9,4,9,3,9,6,10,3,10
%N A053475 1 + the number of iterations of A051953 (Euler-cototient) function needed to reach 0, starting at n.
%C A053475 Analogous sequences of iteration-lengths for A000005 or A000010 are A036459 and A049108 resp. The length values of 3 occur if the initial value is prime resulting in {p,1,0} iterations.
%H A053475 T. D. Noe, <a href="/A053475/b053475.txt">Table of n, a(n) for n = 1..10000</a>
%F A053475 a(n) = A076640(n) + 1. - _Michael De Vlieger_, Jul 04 2016
%e A053475 Starting with n=18, the iterations of A051953 are as follows: {18,12,8,4,2,1,0}. The length of this sequence is 7, so a(18) = 7. The function is applied a(n)-1 times.
%t A053475 Table[Length@ NestWhileList[# - EulerPhi@ # &, n, # > 0 &], {n, 84}] (* _Michael De Vlieger_, Jul 04 2016 *)
%Y A053475 Cf. A000005, A000010, A051953, A036459, A049108, A076640.
%K A053475 nonn
%O A053475 1,1
%A A053475 _Labos Elemer_, Jan 14 2000