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 A063753 #14 Jun 25 2018 02:55:38
%S A063753 2,6,21,24,54,96,189,216,345,384,420,796,864,1332,1536,1680,2340,3300,
%T A063753 3780,5328,6144,6516,6720,8260,8484,9360,10500,13200,14532,15120,
%U A063753 18340,19476,20580,24576,26064,26628,26880,29700,33396,33936,34020
%N A063753 Numbers k such that cototient(k) is a square and sets a new record for squares.
%H A063753 Harry J. Smith, <a href="/A063753/b063753.txt">Table of n, a(n) for n = 1..275</a>
%o A063753 (PARI)a=0; for(n=1,7000,x=n-eulerphi(n); if(issquare(x),b=x; if(b>a,a=b; print(n))))
%o A063753 (PARI) { n=0; a=0; for (m=1, 10^9, if (issquare(b=m - eulerphi(m)), if (b>a, a=b; write("b063753.txt", n++, " ", m); if (n==275, break))) ) } \\ _Harry J. Smith_, Aug 29 2009
%Y A063753 Cf. A051953.
%K A063753 easy,nonn
%O A063753 1,1
%A A063753 _Jason Earls_, Aug 11 2001
%E A063753 More terms from _Dean Hickerson_, Aug 22 2001