A259518 Number of (n+1) X (2+1) 0..1 arrays with each 2 X 2 subblock having clockwise pattern 0000 0001 0011 0101 or 1111.

38, 208, 1122, 6100, 33162, 180370, 981092, 5336678, 29029222, 157906912, 858948710, 4672329330, 25415560796, 138250260726, 752024907134, 4090708107616, 22251780062734, 121040588343338, 658411326480860

Offset

1,1

Links

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

Formula

Empirical: a(n) = 7*a(n-1) - 7*a(n-2) - 10*a(n-3) + 10*a(n-4) + 2*a(n-5).

Empirical g.f.: 2*x*(19 - 29*x - 34*x^2 + 41*x^3 + 8*x^4) / (1 - 7*x + 7*x^2 + 10*x^3 - 10*x^4 - 2*x^5). - Colin Barker, Dec 25 2018

Example

Some solutions for n=4:
..1..0..0....1..0..0....0..1..0....0..0..1....0..0..1....1..0..0....0..1..0
..0..0..0....1..0..1....0..1..0....0..0..1....0..1..0....1..0..0....0..0..1
..1..1..1....0..0..1....1..0..0....0..0..0....1..0..1....0..0..0....0..1..0
..0..0..0....0..0..0....0..0..1....0..0..1....0..0..0....0..0..0....0..0..0
..0..0..1....1..1..1....0..1..0....1..0..1....0..1..0....1..1..0....1..0..1

Crossrefs

Column 2 of A259524.

Sequence in context: A124238 A020870 A211502 * A209250 A165068 A160281

Adjacent sequences: A259515 A259516 A259517 * A259519 A259520 A259521

Keyword

nonn

Author

R. H. Hardin, Jun 29 2015

Status

approved