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%I #8 Dec 28 2023 22:11:36
%S 1,2,8,30,114,414,1561,6227,25712,107071,445688,1860037,7822241,
%T 33194789,141813340,608193866,2615140082,11275208902,48764348038,
%U 211550067336,920159818053,4010884160844,17515357388423,76622591861147
%N Number of 3 X n arrays containing n copies of 0..3-1 with no element 1 greater than its west or north neighbor modulo 3 and the upper left element equal to 0.
%C Row 3 of A266318.
%H R. H. Hardin, <a href="/A266319/b266319.txt">Table of n, a(n) for n = 1..100</a>
%e Some solutions for n=4
%e ..0..0..2..1....0..2..2..1....0..0..2..1....0..0..2..1....0..2..1..1
%e ..2..2..1..0....2..2..1..0....0..2..2..1....0..2..2..1....2..1..0..0
%e ..2..1..1..0....1..1..0..0....0..2..1..1....2..1..1..0....2..1..0..2
%Y Cf. A266318.
%K nonn
%O 1,2
%A _R. H. Hardin_, Dec 27 2015