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 A090556 #12 May 01 2016 12:08:33 %S A090556 1,2,3,4,5,8,10,12,13,21,26,28,35,39,45,52,56,65,97,119,153,193,221, %T A090556 291,357,386,388,416,442,448,476,485,579,595,663,765,769,965,1105, %U A090556 1455,1538,1544,1552,1649,1799,2307,2313,2895,3076,3088,3104,3281,3341,3845,4947 %N A090556 Beginning with 1, a(n) = least number m > a(n-1) such that phi(a(n-1)) divides phi(m). %H A090556 Ivan Neretin, <a href="/A090556/b090556.txt">Table of n, a(n) for n = 1..308</a> %F A090556 a(1)=1, then a(n+1) = A069797(a(n)). - _Ivan Neretin_, May 01 2016 %t A090556 NestList[Function[n, SelectFirst[Range[n + 1, 10^4], Divisible[EulerPhi@ #, EulerPhi@ n] &]], 1, 54] (* _Michael De Vlieger_, May 01 2016, Version 10 *) %Y A090556 Cf. A014573, A090557. %K A090556 nonn %O A090556 1,2 %A A090556 _Amarnath Murthy_, Dec 10 2003 %E A090556 Corrected and extended by Sam Handler (sam_5_5_5_0(AT)yahoo.com), Nov 03 2004