A259291 - OEIS

%I #8 Dec 25 2018 06:22:23

%S 26,94,322,1134,3938,13774,48002,167598,584610,2040206,7118274,

%T 24838766,86667746,302412110,1055197186,3681898030,12847185954,

%U 44827572494,156416277058,545781633518,1904389428834,6644964604110,23186198459522

%N Number of (n+1) X (2+1) 0..1 arrays with each 2 X 2 subblock having clockwise pattern 0001 0101 or 0111.

%H R. H. Hardin, <a href="/A259291/b259291.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 3*a(n-1) + 4*a(n-2) - 8*a(n-3).

%F Empirical g.f.: 2*x*(13 + 8*x - 32*x^2) / (1 - 3*x - 4*x^2 + 8*x^3). - _Colin Barker_, Dec 25 2018

%e Some solutions for n=4:

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

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

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

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

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

%Y Column 2 of A259297.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jun 23 2015