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 A010387 #16 Dec 25 2019 15:31:26 %S A010387 0,1,4,6,9,11,14,16,19,21,24 %N A010387 Squares mod 25. %t A010387 Union[PowerMod[Range[25], 2, 25]] (* _Alonso del Arte_, Dec 25 2019 *) %o A010387 (Sage) [quadratic_residues(25)] # _Zerinvary Lajos_, May 24 2009 %o A010387 (Scala) (1 to 25).map(n => (n * n) % 25).toSet.toSeq.sorted // _Alonso del Arte_, Dec 25 2019 %Y A010387 Cf. A028738. %K A010387 nonn,fini,full,easy %O A010387 1,3 %A A010387 _N. J. A. Sloane_