%I #7 Apr 22 2019 13:50:24
%S 1,1,1,0,1,1,1,1,0,0,1,0,1,0,0,0,1,0,1,0,1,0,1,1,0,0,1,1,1,0,1,1,0,0,
%T 0,0,1,0,0,0,1,0,1,0,0,0,1,0,0,0,0,0,1,1,0,0,0,0,1,0,1,0,0,0,0,0,1,1,
%U 1,0,1,0,1,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,0,1,1,0,0,0,1,0,1,0,0
%N a(n) = 1 if cototient of n is a square, 0 otherwise.
%C Characteristic function of A063752.
%H Antti Karttunen, <a href="/A325321/b325321.txt">Table of n, a(n) for n = 1..65537</a>
%H <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>
%F a(n) = A010052(A051953(n)).
%t Array[Boole[IntegerQ@ Sqrt[# - EulerPhi@ #]] &, 105] (* _Michael De Vlieger_, Apr 21 2019 *)
%o (PARI) A325321(n) = issquare(n-eulerphi(n));
%Y Cf. A000010, A010052, A051953, A063752.
%K nonn
%O 1
%A _Antti Karttunen_, Apr 21 2019