login
A259716
Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000001 or 00000011.
1
32, 54, 140, 242, 312, 722, 1388, 1974, 3824, 7718, 12060, 21218, 42344, 71394, 121052, 233030, 412608, 698390, 1295276, 2349522, 4031384, 7276274, 13283916, 23174102, 41199248, 74964486, 132548156, 234319298, 423455688, 755086082
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 4*a(n-3) + 3*a(n-4).
Empirical g.f.: 2*x*(16 + 27*x + 70*x^2 + 57*x^3) / (1 - 4*x^3 - 3*x^4). - Colin Barker, Dec 26 2018
EXAMPLE
Some solutions for n=4:
..1..1..0....0..0..1....0..0..0....0..1..1....0..0..0....1..0..0....0..0..1
..0..1..0....0..0..1....0..0..1....0..1..0....0..0..0....0..1..0....0..1..0
..0..0..0....0..0..0....0..0..0....0..0..0....0..0..1....0..0..0....0..0..0
..0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0
..1..0..0....1..1..0....0..1..0....0..1..0....0..0..0....1..0..0....0..1..0
..1..0..0....0..0..0....1..0..0....0..1..0....1..1..0....0..0..0....0..1..0
CROSSREFS
Column 1 of A259723.
Sequence in context: A165000 A259723 A118617 * A033907 A033549 A117478
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jul 03 2015
STATUS
approved