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 A243144 #8 May 31 2014 15:53:41 %S A243144 0,7,204,1891,10846,46068,159830,477033,1268614,3075291,6911894, %T A243144 14580293,29145928,55620816,101945063,180327134,309087474 %N A243144 Number of inequivalent (mod D_3) ways to place 5 points on a triangular grid of side n so that they are not vertices of an equilateral triangle of any orientation. %F A243144 a(n) = (n^10 + 5*n^9 - 30*n^8 - 150*n^7)/23040 + O(n^6). %Y A243144 Cf. A243141, A240442, A001399, A227327, A243142, A243143. %K A243144 nonn,more %O A243144 3,2 %A A243144 _Heinrich Ludwig_, May 31 2014