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 A055159 #3 Mar 30 2012 18:51:25 %S A055159 459,1467,1245789,123456789,123456789 %N A055159 n has distinct digits in ascending order and n=a-b where a has the digits of n in descending order and b has the digits of n in another order (a and b perhaps with extra zeros). %D A055159 Denis Borris, Ken Duisenberg's Puzzle of the Week, April 20, 2000 %H A055159 <a href="http://www.ecst.csuchico.edu/~kend/potw/archive/000420sol.html">Source</a> %F A055159 a(n)=A055158(n)-A055157(n) %e A055159 459=954-495 %Y A055159 Cf. A055162. %K A055159 fini,full,base,nonn %O A055159 0,1 %A A055159 _Henry Bottomley_, Apr 27 2000