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 A039286 #12 Jun 28 2021 04:34:24 %S A039286 20,29,45,54,70,79,95,101,102,103,105,110,115,134,139,144,146,147,148, %T A039286 154,170,179,195,204,220,226,227,228,230,235,240,259,264,269,271,272, %U A039286 273,279,295,304,320,329,345,351,352,353,355,360,365,384,389,394,396 %N A039286 Numbers whose base-5 representation has the same nonzero number of 0's and 4's. %Y A039286 Cf. A007091. %K A039286 nonn,base,easy %O A039286 1,1 %A A039286 _Olivier Gérard_