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 A247570 #7 Sep 20 2014 14:12:26 %S A247570 2,4,4,10,7,21,8,10,20,55,13,39,42,31,32,136,19,171,40 %N A247570 Base-9 state complexity of partitioned deterministic finite automaton (PDFA) for the periodic sequence (123...n)*. %H A247570 Klaus Sutner and Sam Tetruashvili, <a href="http://www.cs.cmu.edu/~sutner/papers/auto-seq.pdf">Inferring automatic sequences</a> (see table on the p. 5). %Y A247570 Cf. similar sequences listed in A247566. %K A247570 nonn,more %O A247570 2,1 %A A247570 _Vincenzo Librandi_, Sep 20 2014