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 A129879 #5 Mar 30 2013 04:52:22
%S A129879 1,0,3,9,42,182,821,3754
%N A129879 Sequence a_{a_n} arising in enumeration of arrays of directed blocks (see Quaintance reference for precise definition), where a_n is A129878.
%D A129879 Jocelyn Quaintance, Combinatoric Enumeration of Two-Dimensional Proper Arrays, Discrete Math., 307 (2007), 1844-1864.
%F A129879 See Quaintance reference for generating functions that produce A129872-A129886.
%K A129879 nonn,more
%O A129879 1,3
%A A129879 _N. J. A. Sloane_, May 26 2007