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A028727 Nonsquares mod 14. 1

%I #10 Dec 14 2019 08:16:04

%S 3,5,6,10,12,13

%N Nonsquares mod 14.

%e Since 6 is not a perfect square and there are no solutions to x^2 = 6 mod 14 in integers, 6 is in the sequence.

%e Although 7 is not a perfect square either, there are solutions to x^2 = 7 mod 14, namely odd multiples of 7. Thus 7 is not in the sequence.

%t Complement[Range[0, 13], PowerMod[Range[14], 2, 14]] (* _Alonso del Arte_, Dec 14 2019 *)

%o (Scala) (0 to 13).diff((1 to 14).map(n => (n * n) % 14)) // _Alonso del Arte_, Dec 14 2019

%Y Cf. A010377.

%K nonn,fini,full

%O 1,1

%A _N. J. A. Sloane_

%E Incorrect term 7 removed by _Alonso del Arte_, Dec 14 2019

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Last modified April 25 11:39 EDT 2024. Contains 371969 sequences. (Running on oeis4.)