A183691 Number of (n+1) X 3 0..2 arrays with every 2 X 2 subblock nonsingular.

314, 4594, 66658, 969978, 14100346, 205047906, 2981428242, 43352455562, 630370287594, 9166011482354, 133279732667138, 1937974996756378, 28179423476635226, 409747282346950786, 5957993760514619122

Offset

1,1

Comments

Column 2 of A183698.

Links

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

Formula

Empirical: a(n) = 8*a(n-1) + 91*a(n-2) + 74*a(n-3) - 208*a(n-4).

Empirical g.f.: 2*x*(157 + 1041*x + 666*x^2 - 2288*x^3) / (1 - 8*x - 91*x^2 - 74*x^3 + 208*x^4). - Colin Barker, Apr 04 2018

Example

Some solutions for 5 X 3:
..0..2..0....0..2..0....0..1..2....0..2..0....0..1..0....0..1..1....0..1..0
..1..2..1....2..2..2....2..1..0....2..2..1....2..1..1....1..1..0....1..0..2
..2..0..1....1..0..1....2..0..2....2..0..1....1..2..0....2..1..2....2..2..2
..2..1..2....0..2..1....2..1..2....1..2..0....2..1..2....0..1..1....0..1..0
..1..0..2....1..2..2....2..0..1....1..1..1....1..0..1....1..2..0....2..0..2

Crossrefs

Cf. A183698.

Sequence in context: A157621 A230945 A377769 * A284078 A231021 A104819

Adjacent sequences: A183688 A183689 A183690 * A183692 A183693 A183694

Keyword

nonn

Author

R. H. Hardin, Jan 06 2011

Status

approved