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 A239372 #8 Mar 19 2014 12:12:08
%S A239372 1,1,4,27,250,2915,40746,661304
%N A239372 Words of length n over the alphabet {0,...,n-1} that avoid the pattern 1212.
%Y A239372 Cf. A239295.
%K A239372 nonn,more
%O A239372 0,3
%A A239372 _Chad Brewbaker_, Mar 17 2014