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 A112513 #1 Sep 21 2005 03:00:00
%S A112513 3,13,1113,3113,2321,221311,223113,222321,421311,14123113,41141223,
%T A112513 24312213,32142321,23322114,32232114,23322114,32232114,23322114,
%U A112513 32232114,23322114
%N A112513 Same as A063850, Say what you see in previous term, but starting with 3.
%C A112513 Eventually periodic.
%o A112513 (Perl) #!/usr/bin/perl -l use strict; use warnings; die "Usage: $0 <number> " unless @ARGV==1; $_=shift; { print; my (%cnt, %saw); $cnt{$_}++ for /./g; s/./ $saw{$&}++ ? '' : $cnt{$&} . $& /ge; <>, redo; } __END__
%Y A112513 Cf. A005150, A005151, A063850, A112512-A112515.
%K A112513 base,easy,nonn
%O A112513 1,1
%A A112513 Michele Dondi (blazar(AT)lcm.mi.infn.it), Sep 09 2005