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 A028730 #18 Dec 17 2019 05:56:10 %S A028730 3,5,6,7,10,11,12,14 %N A028730 Nonsquares mod 17. %C A028730 Numbers n such that x^2 == n mod 17 has no solution. %t A028730 p = 17; Complement[Range[p - 1], Union[Mod[Range[(p - 1)/2]^2, p]]] (* _Harvey P. Dale_, Apr 26 2011 *) %t A028730 Select[Range[0, 16], JacobiSymbol[#, 17] == -1 &] (* _Alonso del Arte_, Dec 17 2019 *) %o A028730 (Scala) (0 to 16).diff((1 to 17).map(n => (n * n) % 17)) // _Alonso del Arte_, Dec 17 2019 %Y A028730 Cf. A010379, A136806. %K A028730 nonn,fini,full %O A028730 1,1 %A A028730 _N. J. A. Sloane_