%I #9 Jun 21 2018 10:32:06

%S 8,64,216,940,3776,15652,64176,263976,1084380,4456764,18314496,

%T 75265524,309304372,1271098480,5223614592,21466618480,88217749664,

%U 362533690524,1489843800060,6122560903368,25160860321572,103399362536912

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

%C Column 4 of A207254.

%H R. H. Hardin, <a href="/A207250/b207250.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 2*a(n-1) + 7*a(n-2) + 2*a(n-3) + 13*a(n-4) + 27*a(n-5) + 8*a(n-6) - 4*a(n-7) - 4*a(n-8) - 2*a(n-9) + a(n-10).

%F Empirical g.f.: 4*x*(2 + 12*x + 8*x^2 + 11*x^3 + 38*x^4 + 10*x^5 - 10*x^6 - 6*x^7 - 4*x^8 + 2*x^9) / (1 - 2*x - 7*x^2 - 2*x^3 - 13*x^4 - 27*x^5 - 8*x^6 + 4*x^7 + 4*x^8 + 2*x^9 - x^10). - _Colin Barker_, Jun 21 2018

%e Some solutions for n=4:

%e ..0..1..0..0....1..1..0..0....1..1..0..0....1..0..0..0....0..0..0..0

%e ..1..1..1..0....0..0..0..0....1..1..0..0....0..0..0..0....0..0..0..0

%e ..1..1..1..1....0..0..0..0....0..1..1..0....0..0..0..0....1..0..0..0

%e ..0..1..1..1....1..0..0..0....0..1..1..0....1..0..0..0....1..1..0..0

%Y Cf. A207254.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 16 2012