%I #10 Dec 22 2019 03:37:01
%S 2,3,5,6,7,8,10,11,12,13,14,15,17,18,19,20,22,23,24,26,27,29,30,31,32,
%T 33,34,35,38,39,40,41,42,43,44,45,46,47,48,50,51,52,53,54,55,56,58,59,
%U 61,62,63,65,66,67,68,69,70,71,73,74,75,76,77,78,79,80,82,83
%N Nonsquares mod 84.
%t Complement[Range[0, 83], PowerMod[Range[84], 2, 84]] (* _Alonso del Arte_, Dec 21 2019 *)
%o (Scala) (0 to 83).diff((1 to 84).map(n => (n * n) % 84)) // _Alonso del Arte_, Dec 21 2019
%Y Cf. A010445.
%K nonn,fini,full,easy
%O 1,1
%A _N. J. A. Sloane_