%I #17 Dec 24 2019 13:15:08
%S 0,1,4,9,16,25,28,36,40,49,52,64
%N Squares mod 72.
%t Union[PowerMod[Range[72], 2, 72]] (* _Alonso del Arte_, Dec 24 2019 *)
%o (Sage) [quadratic_residues(72)] # _Zerinvary Lajos_, May 24 2009
%o (Scala) (1 to 72).map(n => (n * n) % 72).toSet.toSeq.sorted // _Alonso del Arte_, Dec 24 2019
%o (PARI) Set(lift(apply(sqr,Mod([1..16],72)))) \\ _Charles R Greathouse IV_, Dec 24 2019
%Y Cf. A028785.
%K nonn,fini,full,easy
%O 1,3
%A _N. J. A. Sloane_