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 A027101 #4 Mar 30 2012 18:56:14 %S A027101 1,1,3,9,18,49,127,331,883,2376,6439,17591,48347,133589,370883, %T A027101 1033997,2893498,8124303,22880569,64616728,182943204,519146325, %U A027101 1476337528,4206621803,12008000771,34335363519,98332343337,282026580873 %N A027101 a(n) = diagonal sum of right justified array T given by A027082. %K A027101 nonn %O A027101 0,3 %A A027101 _Clark Kimberling_