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 A010442 #17 Feb 26 2024 14:19:05 %S A010442 0,1,4,7,9,10,13,16,19,22,25,28,31,34,36,37,40,43,46,49,52,55,58,61, %T A010442 63,64,67,70,73,76,79 %N A010442 Squares mod 81. %t A010442 Union[PowerMod[Range[81], 2, 81]] (* _Alonso del Arte_, Dec 27 2019 *) %o A010442 (Sage) [quadratic_residues(81)] # _Zerinvary Lajos_, May 28 2009 %o A010442 (Scala) (1 to 81).map(n => (n * n) % 81).toSet.toSeq.sorted // _Alonso del Arte_, Dec 27 2019 %Y A010442 Cf. A028794, A055047. %K A010442 nonn,fini,full,easy %O A010442 1,3 %A A010442 _N. J. A. Sloane_