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Nonsquares mod 54.
1

%I #15 Sep 08 2022 08:44:50

%S 2,3,5,6,8,11,12,14,15,17,18,20,21,23,24,26,29,30,32,33,35,38,39,41,

%T 42,44,45,47,48,50,51,53

%N Nonsquares mod 54.

%t Complement[Range[0, 53], PowerMod[Range[54], 2, 54]] (* _Alonso del Arte_, Dec 27 2019 *)

%o (Scala) (0 to 53).diff((1 to 54).map(n => (n * n) % 54)) // _Alonso del Arte_, Dec 27 2019

%o (Magma) [ n: n in [0..53] | not IsSquare(R! n) where R:= ResidueClassRing(54)]; // _Vincenzo Librandi_, Dec 28 2019

%Y Cf. A010415.

%K nonn,fini,full,easy

%O 1,1

%A _N. J. A. Sloane_