%I #14 Jun 25 2018 02:55:38

%S 2,6,21,24,54,96,189,216,345,384,420,796,864,1332,1536,1680,2340,3300,

%T 3780,5328,6144,6516,6720,8260,8484,9360,10500,13200,14532,15120,

%U 18340,19476,20580,24576,26064,26628,26880,29700,33396,33936,34020

%N Numbers k such that cototient(k) is a square and sets a new record for squares.

%H Harry J. Smith, <a href="/A063753/b063753.txt">Table of n, a(n) for n = 1..275</a>

%o (PARI)a=0; for(n=1,7000,x=n-eulerphi(n); if(issquare(x),b=x; if(b>a,a=b; print(n))))

%o (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 Cf. A051953.

%K easy,nonn

%O 1,1

%A _Jason Earls_, Aug 11 2001

%E More terms from _Dean Hickerson_, Aug 22 2001