%I #6 Aug 12 2016 06:54:17
%S 4,54,420,3088,25226,239994,2338286,23240168,232006814,2352889414,
%T 24069853302,248560741574,2582277394354,26997628173380,
%U 283652378887212,2994183763030920,31727834772912212,337396544704648686
%N Number of 3Xn arrays containing n copies of 0..3-1 avoiding the pattern down-up in every row and column.
%C Row 3 of A269505.
%H R. H. Hardin, <a href="/A269507/b269507.txt">Table of n, a(n) for n = 1..48</a>
%e Some solutions for n=4
%e ..1..1..2..0. .1..0..0..1. .0..0..2..1. .0..0..2..2. .0..1..2..1
%e ..1..1..2..2. .2..1..1..2. .0..2..2..1. .1..2..1..1. .0..2..2..1
%e ..0..0..0..2. .0..2..2..0. .2..1..1..0. .1..2..0..0. .2..0..0..1
%Y Cf. A269505.
%K nonn
%O 1,1
%A _R. H. Hardin_, Feb 28 2016