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 A066663 #14 Feb 23 2024 01:09:25
%S A066663 1320,1640,1768,1996,2640,3960,13200,16400,19984,19996,26400,39600,
%T A066663 132000,164000,199996,264000,396000,1320000,1640000,1999936,2640000,
%U A066663 3960000,13200000,16400000,16666240,17999488,18515584,19999984,19999996
%N A066663 Numbers n such that phi(n) is a proper substring of n.
%C A066663 Since the ratio n/phi(n) grows very slowly with n (see A091439), this sequence will be equal to A067206 (apart the initial 1) at least for all the terms smaller than 10^103. - _Giovanni Resta_, Apr 14 2017
%H A066663 Giovanni Resta, <a href="/A066663/b066663.txt">Table of n, a(n) for n = 1..65</a> (terms < 10^12)
%e A066663 phi(1320)=320, phi(1640)=640, phi(1768)=768, phi(1996)=996, phi(2640)=640,..., phi(199999999984)=99999999984.
%t A066663 Select[Range[2, 10^5], StringPosition[ ToString@ #, ToString@ EulerPhi@ #] != {} &] (* _Giovanni Resta_, Apr 14 2017 *)
%Y A066663 Cf. A000010, A036433, A091439, A067206.
%K A066663 nonn,base
%O A066663 1,1
%A A066663 _Vladeta Jovovic_, Jan 11 2002
%E A066663 Offset corrected and a(19)-a(29) from _Donovan Johnson_, May 08 2010