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%I A208079 #10 Jan 20 2018 12:40:38
%S A208079 9,81,441,2601,15129,88209,514089,2996361,17464041,101787921,
%T A208079 593263449,3457792809,20153493369,117463167441,684625511241,
%U A208079 3990289900041,23257113888969,135552393433809,790057246713849,4604791086849321
%N A208079 Number of 4 X n 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 0 0 and 0 1 0 vertically.
%C A208079 Row 4 of A208078.
%H A208079 R. H. Hardin, <a href="/A208079/b208079.txt">Table of n, a(n) for n = 1..210</a>
%F A208079 Empirical: a(n) = 5*a(n-1) + 5*a(n-2) - a(n-3).
%F A208079 Conjectures from _Colin Barker_, Jan 20 2018: (Start)
%F A208079 G.f.: 9*x*(1 + 4*x - x^2) / ((1 + x)*(1 - 6*x + x^2)).
%F A208079 a(n) = (9/4)*(2*(-1)^n + (3-2*sqrt(2))^n + (3+2*sqrt(2))^n).
%F A208079 (End)
%e A208079 Some solutions for n=4:
%e A208079 ..1..0..1..0....1..1..0..1....1..1..1..1....0..1..1..0....1..1..1..0
%e A208079 ..1..0..1..1....1..0..1..0....0..1..1..0....1..1..0..0....0..1..1..1
%e A208079 ..0..1..0..1....1..0..1..1....0..1..1..1....1..0..1..1....1..1..0..1
%e A208079 ..1..1..1..0....1..1..0..1....1..1..0..1....0..1..1..1....1..0..1..0
%K A208079 nonn
%O A208079 1,1
%A A208079 _R. H. Hardin_, Feb 23 2012

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