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 A132857 #12 Apr 23 2022 14:11:21
%S A132857 1,1,2,4,4,6,4,10,6,8,6,16,12,20,16,30,22,24,12,30,20,40,30,52,36,60,
%T A132857 42,44,24,52,40,70,32,48,40,40,36,72,40,78,58,60,32,40,24,44,24,70,58,
%U A132857 106,48,60,48,100,60,88,48,48,52,72,40,100,54,72,64,84,40,106,56,100
%N A132857 a(0)=1. a(n) = phi(n+a(n-1)), for n>=1, where phi(m) is the number of positive integers which are <= m and are coprime to m.
%H A132857 Harvey P. Dale, <a href="/A132857/b132857.txt">Table of n, a(n) for n = 0..1000</a>
%e A132857 a(8) + 9 = 6 + 9 = 15. There are 8 positive integers that are <= 15 and are relatively prime to 15. So a(9) = 8.
%t A132857 a = {1}; For[n = 1, n < 90, n++, AppendTo[a, EulerPhi[n + a[[ -1]]]]]; a (* _Stefan Steinerberger_, Nov 24 2007 *)
%t A132857 nxt[{n_,a_}]:={n+1,EulerPhi[n+1+a]}; NestList[nxt,{0,1},70][[All,2]] (* _Harvey P. Dale_, Apr 23 2022 *)
%K A132857 nonn
%O A132857 0,3
%A A132857 _Leroy Quet_, Nov 21 2007
%E A132857 More terms from _Stefan Steinerberger_, Nov 24 2007