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 A270806 #6 Apr 02 2016 18:43:21 %S A270806 0,0,0,0,0,8,27,69,154,309,546,889 %N A270806 A269747(n) - A270805(n). %C A270806 Number of regular tetrahedra in an n-node-per-edge tetrahedral grid that do not have all four vertices on the boundary of the parent grid. %Y A270806 Cf. A269747, A270805. %K A270806 nonn,more %O A270806 0,6 %A A270806 _N. J. A. Sloane_, Apr 02 2016