A259244 - OEIS

%I #7 Dec 24 2018 16:21:32

%S 21,65,192,581,1733,5216,15613,46897,140568,421901,1265269,3796472,

%T 11387877,34165857,102492080,307483605,922431077,2767317200,

%U 8301880013,24905716177,74716886152,224150891421,672451700885,2017355772136

%N Number of (n+1) X (2+1) 0..1 arrays with each 2 X 2 subblock having clockwise pattern 0000 0011 or 0111.

%H R. H. Hardin, <a href="/A259244/b259244.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 3*a(n-1) + 4*a(n-2) - 11*a(n-3) - 3*a(n-4).

%F Empirical g.f.: x*(21 + 2*x - 87*x^2 - 24*x^3) / ((1 - 3*x)*(1 - 4*x^2 - x^3)). - _Colin Barker_, Dec 24 2018

%e Some solutions for n=4:

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

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

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

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

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

%Y Column 2 of A259250.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jun 22 2015