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 A129878 #5 Mar 30 2013 04:52:39 %S A129878 1,3,10,42,178,787,3552,16319 %N A129878 Sequence a_n arising in enumeration of arrays of directed blocks (see Quaintance reference for precise definition). %D A129878 Jocelyn Quaintance, Combinatoric Enumeration of Two-Dimensional Proper Arrays, Discrete Math., 307 (2007), 1844-1864. %F A129878 See Quaintance reference for generating functions that produce A129872-A129886. %K A129878 nonn,more %O A129878 1,2 %A A129878 _N. J. A. Sloane_, May 26 2007