A184190 Half the number of (n+1) X 3 binary arrays with no 2 X 2 subblock containing exactly one 1.

19, 104, 561, 3050, 16581, 90185, 490546, 2668339, 14514611, 78953456, 429474355, 2336164665, 12707780398, 69125130363, 376012453567, 2045354053808, 11125890031367, 60520294171669, 329205663240430, 1790744248612871

Offset

1,1

Comments

Column 2 of A184197.

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

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.: 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, Apr 12 2018

Example

Some solutions for 5 X 3:
..0..1..1....0..1..0....0..0..1....1..0..0....0..1..1....1..1..1....1..1..0
..1..0..1....1..0..1....0..0..1....1..0..0....1..1..1....0..0..1....1..0..1
..1..1..1....1..1..0....1..1..0....1..0..0....0..1..1....1..1..1....1..1..1
..1..1..0....0..0..1....1..1..0....0..1..1....1..1..0....1..1..1....0..1..0
..1..1..1....0..0..1....0..1..0....1..0..0....1..1..0....1..0..0....0..1..0

Crossrefs

Cf. A184197.

Sequence in context: A195460 A195461 A096328 * A300644 A142300 A238108

Adjacent sequences: A184187 A184188 A184189 * A184191 A184192 A184193

Keyword

nonn

Author

R. H. Hardin, Jan 10 2011

Status

approved