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 A195624 #20 Mar 30 2012 17:28:27 %S A195624 3,9,29,93,279 %N A195624 Minimum number of squares removed from an n-dimensional tic-tac-toe board to make winning impossible for either player. %C A195624 A156989 is the main sequence for this entry. Related to the density Hales-Jewett theorem. %H A195624 Steve Landsburg, <a href="http://www.thebigquestions.com/2010/04/08/blogging-tic-tac-toe-and-the-future-of-math/">Blogging, Tic Tac Toe and the Future of Math</a> %F A195624 a(n) = 3^n - A156989(n). %Y A195624 Cf. A156989. %K A195624 nonn,hard %O A195624 2,1 %A A195624 _Charles R Greathouse IV_, Sep 26 2011