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 A023400 #17 Jan 27 2022 22:44:52 %S A023400 2,9,9,2,9,2,2,2,2,2,2,9,9,2,9,9,9,9,2,2,9,2,9,2,9,2,2,9,2,2,9,2,2,9, %T A023400 9,9,9,9,2,2,2,2,2,2,9,2,2,9,9,2,9,9,9,9,9,2,9,2,9,2,2,9,9,9,2,2,9,9, %U A023400 9,2,9,2,2,2,2,9,9,9,9,9,9,9,9,2,9,2,9,2,2,2,9,9,2,2,2,9,9,2,9,9,2,9,9,9,2,2,9,9 %N A023400 If any power of 2 ends with k 2's and 9's, they must be the first k terms of this sequence in reverse order. %H A023400 Ray Chandler, <a href="/A023400/b023400.txt">Table of n, a(n) for n = 1..10000</a> %K A023400 nonn,base %O A023400 1,1 %A A023400 _David W. Wilson_