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 A138486 #9 Sep 18 2023 09:01:49
%S A138486 2,12,1211,3112,122113,133122,222123,134211,31121413,23411412,
%T A138486 22312413,23211432,32231421,21321423,23321421,21321423,23321421,
%U A138486 21321423,23321421,21321423,23321421,21321423,23321421,21321423
%N A138486 Say what you see in previous term, from the right, reporting total number for each digit encountered. Initial term is 2.
%C A138486 After a while sequence has period 2 -> {21321423,23321421}
%e A138486 To get the term after 122113, we say: one 3's, three 1's, two 2's, so 133122
%Y A138486 Cf. A063850, A022482, A005150, A005151, A006751, A006715, A006711, A022506-A022513, A138484, A138485, A138487-A138493.
%K A138486 easy,nonn,base
%O A138486 0,1
%A A138486 _Paolo P. Lava_ and _Giorgio Balzarotti_, Mar 20 2008
%E A138486 Duplicate term 21321423 removed by _Georg Fischer_, Sep 18 2023