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 A089565 #3 Mar 30 2012 17:29:13 %S A089565 9,19,419,5419,35419,735419,12735419,1112735419,131112735419, %T A089565 42131112735419,2642131112735419,102642131112735419, %U A089565 17102642131112735419,1617102642131112735419,201617102642131112735419 %N A089565 Concatenations arising in A089564. %Y A089565 Cf. A089710, A089711, A089560-A089573. %K A089565 base,nonn %O A089565 1,1 %A A089565 _Ray Chandler_, Nov 22 2003