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%I #5 Mar 31 2012 12:37:18
%S 9,81,297,1004,2942,7305,17911,40262,87990,187012,385400,783726,
%T 1564402,3084097,6019187,11629307,22307563,42493220,80468378,
%U 151622295,284370183,531240776,988874960,1834816342,3394683936,6264203818,11531988896
%N Number of 4Xn 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 1 0 0 vertically
%C Row 4 of A207500
%H R. H. Hardin, <a href="/A207501/b207501.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 4*a(n-1) -a(n-2) -10*a(n-3) -3*a(n-4) +28*a(n-5) +4*a(n-6) -32*a(n-7) -15*a(n-8) +26*a(n-9) +8*a(n-10) -6*a(n-11) +8*a(n-12) -4*a(n-13) -13*a(n-14) -2*a(n-15) +11*a(n-16) -2*a(n-17) +a(n-18) -2*a(n-21) +a(n-22)
%e Some solutions for n=4
%e ..1..1..0..1....1..0..1..0....1..1..0..1....1..1..0..1....1..1..1..1
%e ..0..0..1..0....0..1..0..0....1..1..0..1....0..1..0..0....1..1..1..1
%e ..1..1..1..1....1..0..1..0....0..1..0..0....1..1..0..1....1..1..1..1
%e ..1..0..1..0....0..1..0..0....1..0..0..1....0..1..0..1....1..0..1..0
%K nonn
%O 1,1
%A _R. H. Hardin_ Feb 18 2012
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