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 A291177 #15 Jul 24 2021 01:10:36 %S A291177 45,297,356,375,1335,1935,3915,4743,5271,6015,6375,6903,20894,22311, %T A291177 25347,28118,31664,32384,39632,49155,50954,55935,59984,64514,70275, %U A291177 119324,125054,162944,209715,334304,342975,472718,767584,798567,862802,908775,1280096 %N A291177 Numbers k such that s(k) = s(k+1) but phi(k) != phi(k+1), where s(k) = phi(k) + phi(phi(k)) + ... + 1 is the sum of iterated phi (A092693). %C A291177 The restriction phi(k) != phi(k+1) is intended to exclude all the (trivial) terms of A001274. %H A291177 Amiram Eldar, <a href="/A291177/b291177.txt">Table of n, a(n) for n = 1..200</a> %t A291177 s[n_]:=Plus @@ FixedPointList[EulerPhi, n] - (n + 1);seqQ[n_]:=(s[n+1]==s[n])&&(EulerPhi[n+1]!=EulerPhi[n]);Select[Range[10^5],seqQ] %Y A291177 Cf. A001274, A092693. %K A291177 nonn %O A291177 1,1 %A A291177 _Amiram Eldar_, Aug 19 2017