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 A001735 #7 Feb 03 2022 22:49:58 %S A001735 5,5,5,5,5,10,11,12,101,11111 %N A001735 5 in base 10-n. %K A001735 fini,nonn,base,full %O A001735 0,1 %A A001735 _N. J. A. Sloane_