A259716 Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000001 or 00000011.

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

R. H. Hardin, Table of n, a(n) for n = 1..210

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

Adjacent sequences: A259713 A259714 A259715 * A259717 A259718 A259719

Keyword

nonn

Author

R. H. Hardin, Jul 03 2015

Status

approved