This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A028792 #21 Sep 08 2022 08:44:50 %S A028792 3,6,7,12,14,15,17,24,27,28,29,30,33,34,35,37,39,41,43,47,48,53,54,56, %T A028792 57,58,59,60,61,63,66,68,69,70,71,74,75,77,78 %N A028792 Nonsquares mod 79. %F A028792 Legendre symbol (a(n)/79) = -1. - _Alonso del Arte_, Jan 15 2017 %e A028792 x^2 = 7 mod 79 has no solutions, hence 7 is in the sequence. %e A028792 x^2 = 8 mod 79 has the solutions x = 18 and x = 61, so 8 is not in the sequence. %t A028792 Complement[Range[78], PowerMod[Range[78], 2, 79]] (* _Alonso del Arte_, Jan 15 2017 *) %o A028792 (PARI) isok(n) = (n < 79) && (kronecker(n, 79) == -1); \\ _Michel Marcus_, Jan 15 2017 %o A028792 (PARI) isok(n) = (n < 79) && (! issquare(Mod(n, 79))); \\ _Michel Marcus_, Jan 15 2017 %o A028792 (Scala) (0 to 78).diff((1 to 79).map(n => n * n % 79)) // _Alonso del Arte_, Jan 22 2020 %o A028792 (Magma) [n: n in [0..78] | not IsSquare(R! n) where R:= ResidueClassRing(79)]; // _Vincenzo Librandi_, Jan 23 2020 %Y A028792 Cf. A010440 (complement), A096013 (row 79). %K A028792 nonn,fini,full,easy %O A028792 1,1 %A A028792 _N. J. A. Sloane_