OFFSET
1,1
COMMENTS
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..65537
MATHEMATICA
Array[Sign[Sqrt[#] /. (c_: 1) a_^(b_: 0) :> (c a^b)^2 - EulerPhi@ #] &, 100] (* Michael De Vlieger, Nov 18 2017, after Bill Gosper at A007913 *)
PROG
(PARI) for(n=1, 100, print1(sign(core(n)-eulerphi(n)), ", "))
CROSSREFS
KEYWORD
easy,sign
AUTHOR
Benoit Cloitre, May 08 2002
EXTENSIONS
Comment section edited by Antti Karttunen, Nov 18 2017
STATUS
approved