A010389 - OEIS

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A010389

Squares mod 27.

%I #17 Nov 27 2019 01:38:19

%S 0,1,4,7,9,10,13,16,19,22,25

%N Squares mod 27.

%t Union[PowerMod[Range[27], 2, 27]] (* _Alonso del Arte_, Nov 27 2019 *)

%o (Sage) [quadratic_residues(27)] # _Zerinvary Lajos_, May 24 2009

%o (Scala) (1 to 27).map(n => n * n).map(_ % 27).toSet.toSeq.sorted // _Alonso del Arte_, Nov 27 2019

%Y Cf. A028740.

%K nonn,fini,full

%O 1,3

%A _N. J. A. Sloane_