%I #6 Aug 12 2016 06:54:00
%S 2,2,6,31,141,550,2046,8149,34902,152001,652150,2761689,11707811,
%T 50123854,216480177,938377955,4069585995,17658916102,76776575711,
%U 334729181549,1462999055814,6405806909581,28085236208039,123289001886325
%N Number of 3Xn arrays containing n copies of 0..3-1 with no element 1 greater than its west or southwest neighbor modulo 3 and the upper left element equal to 0.
%C Row 3 of A267072.
%H R. H. Hardin, <a href="/A267073/b267073.txt">Table of n, a(n) for n = 1..93</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 ..1..0..2..1....0..2..1..0....0..2..1..1....0..2..2..1....2..2..1..0
%e ..0..2..2..1....2..1..1..0....0..2..2..1....0..2..1..1....2..1..0..0
%Y Cf. A267072.
%K nonn
%O 1,1
%A _R. H. Hardin_, Jan 10 2016