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 A001734 #7 Feb 03 2022 22:49:46 %S A001734 6,6,6,6,10,11,12,20,110,111111 %N A001734 6 in base 10-n. %K A001734 fini,nonn,base,full %O A001734 0,1 %A A001734 _N. J. A. Sloane_