A207560 - OEIS

%I #9 Oct 20 2014 17:08:01

%S 9,81,241,636,2135,6709,23276,78733,277781,973608,3477827,12422849,

%T 44780404,161681185,586480585,2130883040,7761845079,28308582237,

%U 103395253764,377977638085,1382951559309,5062965194920,18545296800603

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

%C Column 4 of A207564.

%H R. H. Hardin, <a href="/A207560/b207560.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 7*a(n-1) -2*a(n-2) -73*a(n-3) +95*a(n-4) +258*a(n-5) -429*a(n-6) -357*a(n-7) +730*a(n-8) +125*a(n-9) -499*a(n-10) +70*a(n-11) +106*a(n-12) -30*a(n-13) for n>14.

%e Some solutions for n=4:

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 18 2012