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 A217750 #7 Mar 23 2013 15:11:24 %S A217750 0,0,0,0,0,0,18,50,88,156,260,392,555,848,1088 %N A217750 Number of tetragonal regions in the exterior of a regular n-gon with all diagonals drawn. %Y A217750 Cf. A067151, A217746. %K A217750 nonn %O A217750 3,7 %A A217750 _Martin Renner_, Mar 23 2013