A208093 - OEIS

%I #9 Dec 30 2012 01:50:43

%S 2,30,1573,192328,43366459,15769674462,8494585220016,6391850672195207,

%T 6435536606760976374,8388789053759733374255,

%U 13792349692923790472807338,28002764873470436036725295426,68986219453948522377865096287773

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

%C Column 3 of A208096

%H R. H. Hardin, <a href="/A208093/b208093.txt">Table of n, a(n) for n = 1..16</a>

%e Some solutions for n=4

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Feb 23 2012