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 A008709 #8 Jul 08 2025 01:20:13 %S A008709 10,11,12,13,14,15,20,22,30,110,1100,111111111111 %N A008709 12 in base 12-n. %K A008709 fini,nonn,base,full %O A008709 0,1 %A A008709 _N. J. A. Sloane_