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A208841 Number of 4 X n 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 1 1 and 1 1 0 vertically.

%I A208841 #9 Nov 05 2014 17:55:04
%S A208841 9,81,171,855,2421,9801,31419,116919,394965,1419849,4902939,17375031,
%T A208841 60551541,213310665,746231931,2622329271,9188418069,32255749449,
%U A208841 113096449755,396852637239,1391845926069,4883081614281,17127968887611
%N A208841 Number of 4 X n 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 1 1 and 1 1 0 vertically.
%C A208841 Row 4 of A208840.
%H A208841 R. H. Hardin, <a href="/A208841/b208841.txt">Table of n, a(n) for n = 1..210</a>
%F A208841 Empirical: a(n) = 2*a(n-1) +7*a(n-2) -6*a(n-3).
%e A208841 Some solutions for n=4:
%e A208841 ..1..1..1..1....0..1..1..1....0..1..1..0....0..1..1..0....1..0..1..1
%e A208841 ..0..1..0..1....0..1..0..1....0..1..1..1....1..1..0..0....0..1..1..0
%e A208841 ..1..1..1..1....0..1..0..1....1..1..1..0....0..1..0..1....1..0..1..1
%e A208841 ..0..1..0..1....0..1..1..1....0..1..1..1....0..1..1..0....0..1..1..0
%Y A208841 Cf. A208840.
%K A208841 nonn
%O A208841 1,1
%A A208841 _R. H. Hardin_, Mar 01 2012