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Number of ways to arrange 7 indistinguishable points on an n X n X n triangular grid so that no three points are in the same row or diagonal.
1

%I #8 Dec 09 2017 03:57:35

%S 0,0,0,0,15,3525,98473,1237434,9821400,57367112,268378248,1059987987,

%T 3661533037,11341971885,32090198922,84099053568,206386405560,

%U 478423135296,1054963957500,2225704950054,4514320792971,8838377453829

%N Number of ways to arrange 7 indistinguishable points on an n X n X n triangular grid so that no three points are in the same row or diagonal.

%C Column 7 of A194480.

%H R. H. Hardin, <a href="/A194479/b194479.txt">Table of n, a(n) for n = 1..24</a>

%e Some solutions for 5 X 5 X 5:

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

%e .....1.0........0.1........0.0........1.0........0.1........0.0........0.0

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

%e ...1.0.0.1....1.0.0.1....0.1.1.0....0.1.1.0....1.0.1.0....0.0.1.1....1.1.0.0

%e ..0.1.1.0.0..0.0.1.1.0..0.1.0.1.0..0.1.0.0.1..0.1.0.1.0..0.1.1.0.0..0.0.1.1.0

%K nonn

%O 1,5

%A _R. H. Hardin_, Aug 26 2011