A208778 - OEIS

%I #12 Jul 06 2018 23:14:32

%S 26,676,156,260,416,676,1092,1768,2860,4628,7488,12116,19604,31720,

%T 51324,83044,134368,217412,351780,569192,920972,1490164,2411136,

%U 3901300,6312436,10213736,16526172,26739908,43266080,70005988,113272068

%N Number of n X 6 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 1 1 and 1 1 1 vertically.

%C Column 6 of A208780.

%H R. H. Hardin, <a href="/A208778/b208778.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = a(n-1) + a(n-2) for n>4.

%F Empirical g.f.: 26*x*(1 + 25*x - 21*x^2 - 22*x^3) / (1 - x - x^2). - _Colin Barker_, Jul 06 2018

%e Some solutions for n=4:

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

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

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

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

%Y Cf. A208780.

%K nonn

%O 1,1

%A _R. H. Hardin_, Mar 01 2012