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Number of ways to arrange 4 indistinguishable points on an n X n X n triangular grid so that no three points are collinear at any angle.
2

%I #8 Dec 09 2017 03:57:11

%S 0,0,6,114,843,4122,14988,45414,119340,281442,608616,1228812,2338779,

%T 4240284,7371414,12354156,20052846,31653108,48726846,73358964,

%U 108233781,156793974,223400004,313529940,433929258,592922880,800651538,1069378740

%N Number of ways to arrange 4 indistinguishable points on an n X n X n triangular grid so that no three points are collinear at any angle.

%C Column 4 of A194136.

%H R. H. Hardin, <a href="/A194132/b194132.txt">Table of n, a(n) for n = 1..78</a>

%e All solutions for 3 X 3 X 3:

%e ....1......1......0......0......1......0

%e ...0.1....1.1....1.1....1.1....1.0....1.1

%e ..1.1.0..0.1.0..1.1.0..1.0.1..0.1.1..0.1.1

%K nonn

%O 1,3

%A _R. H. Hardin_, Aug 17 2011