%I #5 Mar 31 2012 12:37:17
%S 9,81,225,784,2304,5625,14641,33856,77284,173056,372100,795664,
%T 1664100,3433609,7017201,14160169,28355625,56310016,111007296,
%U 217533001,423742225,821280964,1584358416,3043287556,5823216100,11102415424
%N Number of 4Xn 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 0 1 1 vertically
%C Row 4 of A207368
%H R. H. Hardin, <a href="/A207369/b207369.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 4*a(n-1) -a(n-2) -8*a(n-3) -10*a(n-4) +30*a(n-5) +11*a(n-6) -15*a(n-7) -43*a(n-8) +21*a(n-9) -5*a(n-10) +26*a(n-11) +a(n-12) +27*a(n-13) -42*a(n-14) +3*a(n-15) -14*a(n-16) +15*a(n-17) -9*a(n-18) +17*a(n-19) -6*a(n-20) +2*a(n-21) -4*a(n-22) +2*a(n-23) -2*a(n-24) +a(n-25)
%e Some solutions for n=4
%e ..0..1..0..0....1..1..0..1....1..1..0..1....1..1..1..1....0..0..1..0
%e ..1..1..0..1....0..0..1..0....1..1..0..1....1..1..1..1....1..1..0..1
%e ..0..1..0..0....0..1..0..1....0..1..0..0....1..1..1..1....0..0..1..0
%e ..1..1..0..0....0..0..1..0....0..1..0..0....0..1..0..1....1..1..0..1
%K nonn
%O 1,1
%A _R. H. Hardin_ Feb 17 2012