A259291 Number of (n+1) X (2+1) 0..1 arrays with each 2 X 2 subblock having clockwise pattern 0001 0101 or 0111.

26, 94, 322, 1134, 3938, 13774, 48002, 167598, 584610, 2040206, 7118274, 24838766, 86667746, 302412110, 1055197186, 3681898030, 12847185954, 44827572494, 156416277058, 545781633518, 1904389428834, 6644964604110, 23186198459522

Offset

1,1

Links

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

Formula

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

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

Example

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

Crossrefs

Column 2 of A259297.

Sequence in context: A044594 A205998 A205991 * A038654 A010014 A095796

Adjacent sequences: A259288 A259289 A259290 * A259292 A259293 A259294

Keyword

nonn

Author

R. H. Hardin, Jun 23 2015

Status

approved