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 A039565 #10 Jul 01 2021 03:37:58 %S A039565 2,3,12,13,17,18,29,45,62,63,67,68,87,88,92,93,101,105,139,144,147, %T A039565 148,179,195,204,220,227,228,235,240,259,271,279,295,312,313,317,318, %U A039565 337,338,342,343,351,355,384,396,404,420,437,438,442,443,462,463,467 %N A039565 Numbers whose base-5 representation has the same number of 0's, 1's and 4's. %Y A039565 Cf. A007091. %K A039565 nonn,base,easy %O A039565 1,1 %A A039565 _Olivier Gérard_