A208693 Number of 7 X n 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 1 1 and 1 0 1 vertically.

31, 961, 2449, 34627, 133207, 1332721, 6398617, 53340739, 290904031, 2188890625, 12862463425, 91246001059, 560219364679, 3840575264305, 24195101079817, 162595230479203, 1039929864328591, 6907596215160961, 44573099803921777

Offset

1,1

Comments

Row 7 of A208688.

Links

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

Formula

Empirical: a(n) = a(n-1) + 39*a(n-2) + 9*a(n-3) - 180*a(n-4).

Empirical g.f.: 31*x*(1 + 30*x + 9*x^2 - 180*x^3) / ((1 + 5*x)*(1 - 6*x - 9*x^2 + 36*x^3)). - Colin Barker, Jul 05 2018

Example

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

Crossrefs

Cf. A208688.

Sequence in context: A207274 A207767 A207734 * A207563 A207418 A223393

Adjacent sequences: A208690 A208691 A208692 * A208694 A208695 A208696

Keyword

nonn

Author

R. H. Hardin, Mar 01 2012

Status

approved