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 A217749 #7 Mar 23 2013 15:11:05 %S A217749 0,0,0,0,7,24,45,70,121,180,273,406,555,784,1071 %N A217749 Number of triangular regions in the exterior of a regular n-gon with all diagonals drawn. %Y A217749 Cf. A062361, A217746. %K A217749 nonn %O A217749 3,5 %A A217749 _Martin Renner_, Mar 23 2013