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 A027912 #4 Mar 30 2012 18:56:15 %S A027912 1,5,28,156,880,5005,28665,165104,955434,5550755,32355917,189147400, %T A027912 1108476720,6510243495,38308997100,225810489168,1333057076890 %N A027912 T(2n-1,n-2), T given by A027907. %K A027912 nonn %O A027912 2,2 %A A027912 _Clark Kimberling_