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Squares mod 84.
1

%I #22 Dec 22 2019 03:36:56

%S 0,1,4,9,16,21,25,28,36,37,49,57,60,64,72,81

%N Squares mod 84.

%t Union[Mod[Range[84]^2, 84]] (* _Harvey P. Dale_, Jan 09 2011 *)

%o (Sage) [quadratic_residues(84)] # _Zerinvary Lajos_, May 28 2009

%o (Scala) (1 to 84).map(n => (n * n) % 84).toSet.toSeq.sorted // _Alonso del Arte_, Dec 21 2019

%Y Cf. A028797.

%K nonn,fini,full,easy

%O 1,3

%A _N. J. A. Sloane_