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%I #6 Aug 12 2016 06:53:58
%S 6,12,36,114,420,1584,6228,24930,101376,417504,1734876,7271238,
%T 30667068,130119672,554721564,2375331042,10209040920,44027206416,
%U 190434749196,825936571446,3590858184996,15646265986056,68311732725204
%N Number of 3Xn arrays containing n copies of 0..3-1 with no equal horizontal or vertical neighbors.
%C Row 3 of A264954.
%H R. H. Hardin, <a href="/A264955/b264955.txt">Table of n, a(n) for n = 1..123</a>
%e Some solutions for n=4
%e ..2..1..0..2....0..2..0..2....0..1..2..1....0..2..1..2....1..0..1..2
%e ..0..2..1..0....2..1..2..1....2..0..1..2....2..1..0..1....0..2..0..1
%e ..2..1..0..1....1..0..1..0....0..1..2..0....0..2..1..0....2..0..1..2
%Y Cf. A264954.
%K nonn
%O 1,1
%A _R. H. Hardin_, Nov 29 2015
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