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 A033867 #6 Mar 30 2012 18:35:33 %S A033867 1,11,121,1111,4884,45254,44044,233332,233332,88555588,88555588, %T A033867 88555588,52788725,8836886388,8836886388,8836886388,5233333325, %U A033867 5233333325,89540004598,16967744776961,16668488486661,8813200023188 %N A033867 Palindrome reached from A033866(n) by Reverse-then-add. %K A033867 nonn,base %O A033867 1,2 %A A033867 _David W. Wilson_