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 A239378 #6 Mar 19 2014 13:04:56
%S A239378 1,1,4,27,252,2935,40300,630392
%N A239378 Words of length n over the alphabet {0,...,n-1} that avoid the pattern 1312.
%Y A239378 Cf. A239295.
%K A239378 nonn,more
%O A239378 0,3
%A A239378 _Chad Brewbaker_, Mar 17 2014