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A207993 Number of n X n 0..2 arrays with new values 0..2 introduced in row major order and no element equal to any horizontal or vertical neighbor (colorings ignoring permutations of colors).

%I A207993 #12 Sep 23 2019 05:34:55
%S A207993 1,3,41,1302,96831,16932816,6978332618,6787438272198,
%T A207993 15595829208171337,84713253582265127190,1088296274542436098185362,
%U A207993 33079232010276428576508643620,2379573338713223879592059518246838
%N A207993 Number of n X n 0..2 arrays with new values 0..2 introduced in row major order and no element equal to any horizontal or vertical neighbor (colorings ignoring permutations of colors).
%C A207993 Diagonal of A207997.
%H A207993 R. H. Hardin, <a href="/A207993/b207993.txt">Table of n, a(n) for n = 1..16</a>
%e A207993 Some solutions for n=4
%e A207993 ..0..1..0..1....0..1..2..0....0..1..2..0....0..1..2..0....0..1..2..1
%e A207993 ..1..2..1..0....1..0..1..2....2..0..1..2....1..2..0..2....2..0..1..2
%e A207993 ..2..0..2..1....2..1..2..0....1..2..0..1....2..0..1..0....1..2..0..1
%e A207993 ..0..1..0..2....0..2..0..1....2..1..2..0....1..2..0..1....2..0..1..0
%t A207993 A207997 = Import["https://oeis.org/A207997/b207997.txt", "Table"][[All, 2]];
%t A207993 a[n_] := A207997[[2 n^2 - 2 n + 1]];
%t A207993 Table[a[n], {n, 1, 16}] (* _Jean-François Alcover_, Sep 23 2019 *)
%K A207993 nonn
%O A207993 1,2
%A A207993 _R. H. Hardin_, Feb 22 2012