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 A194476 #13 May 05 2018 08:06:30 %S A194476 0,0,6,114,879,4284,15729,47565,124803,293733,634293,1277133,2426424, %T A194476 4389567,7615062,12739902,20647962,32540958,50023656,75205116, %U A194476 110817861,160356966,228241167,319998195,442476645,604086795,815072895,1087819551 %N A194476 Number of ways to arrange 4 indistinguishable points on an n X n X n triangular grid so that no three points are in the same row or diagonal. %C A194476 Column 4 of A194480. %H A194476 R. H. Hardin, <a href="/A194476/b194476.txt">Table of n, a(n) for n = 1..112</a> %F A194476 Empirical: a(n) = (1/384)*n^8 + (1/96)*n^7 - (5/64)*n^6 + (13/240)*n^5 + (27/128)*n^4 - (23/96)*n^3 - (13/96)*n^2 + (7/40)*n. %F A194476 Empirical g.f.: x^3*(2 + 20*x + 23*x^2 - 9*x^3 - x^4) / (1 - x)^9. - _Colin Barker_, May 05 2018 %e A194476 All solutions for 3 X 3 X 3: %e A194476 ....0......1......0......1......1......0 %e A194476 ...1.1....0.1....1.1....1.1....1.0....1.1 %e A194476 ..0.1.1..1.1.0..1.1.0..0.1.0..0.1.1..1.0.1 %Y A194476 Cf. A194480 %K A194476 nonn %O A194476 1,3 %A A194476 _R. H. Hardin_, Aug 26 2011