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 A001733 #7 Feb 03 2022 22:49:33 %S A001733 7,7,7,10,11,12,13,21,111,1111111 %N A001733 7 in base 10-n. %K A001733 fini,nonn,base,full %O A001733 0,1 %A A001733 _N. J. A. Sloane_