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 A234353 #11 Apr 19 2016 07:48:38 %S A234353 8,140,1290,7374,32477,116420,358112,976063,2425756,5560046,11946923, %T A234353 24274195,46975815,87140153 %N A234353 Number of non-equivalent (mod D_3) ways to arrange 5 indistinguishable points on a triangular grid of side n so that no three points are collinear. %C A234353 Column 5 of triangle A234350. %C A234353 Without the restriction "non-equivalent (mod D_3)" the numbers are given by A194133. %e A234353 There are a(4) = 8 non-equivalent ways to arrange 5 indistinguishable points (x) on a triangular grid of side 4. Some examples: %e A234353 x x . . . %e A234353 x x . . x . x x x . %e A234353 . . . x . x x . x . x . x . x %e A234353 . x x . . x x . . x x . x . . x . x . x %Y A234353 Cf. A234350, A194133 %Y A234353 Arranging 3 points: A234351 %Y A234353 Arranging 4 points: A234352 %Y A234353 Arranging 6 points: A234354 %K A234353 nonn,more %O A234353 4,1 %A A234353 _Heinrich Ludwig_, Dec 30 2013 %E A234353 a(14)-a(17) from _Heinrich Ludwig_, Apr 19 2016