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Number of nX3 nonnegative integer arrays with new values 0 upwards introduced in row major order and no element equal to any horizontal or antidiagonal neighbor (colorings ignoring permutations of colors)
2

%I #6 Mar 31 2012 12:37:22

%S 2,42,2906,433252,113503692,46538017584,27700815674032,

%T 22702140562948192,24626774613248937584,34296243004533645925408,

%U 59839415643338575851475744,128222446504879248765189962560,331858429902640216546970620625280

%N Number of nX3 nonnegative integer arrays with new values 0 upwards introduced in row major order and no element equal to any horizontal or antidiagonal neighbor (colorings ignoring permutations of colors)

%C Column 3 of A208301

%H R. H. Hardin, <a href="/A208297/b208297.txt">Table of n, a(n) for n = 1..49</a>

%e Some solutions for n=4

%e ..0..1..0....0..1..0....0..1..2....0..1..0....0..1..0....0..1..2....0..1..2

%e ..0..1..0....0..1..0....0..1..2....0..1..0....2..3..0....0..3..1....0..3..0

%e ..0..1..0....2..1..2....0..1..0....0..1..0....0..2..0....0..2..0....0..1..0

%e ..0..2..1....0..1..0....0..1..0....0..1..0....0..1..0....3..1..0....0..3..0

%K nonn

%O 1,1

%A _R. H. Hardin_ Feb 25 2012