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 A039566 #10 Jul 01 2021 03:37:55 %S A039566 1,4,6,9,21,24,31,34,46,49,53,65,77,85,106,109,121,124,138,142,156, %T A039566 159,171,174,178,190,202,210,231,234,246,249,258,266,269,273,278,290, %U A039566 326,329,330,345,353,365,382,386,389,397,402,410,426,429,430,445,477 %N A039566 Numbers whose base-5 representation has the same number of 0's, 2's and 3's. %Y A039566 Cf. A007091. %K A039566 nonn,base,easy %O A039566 1,2 %A A039566 _Olivier Gérard_