A186044 Number of (n+2) X 3 binary arrays with each 3 X 3 subblock singular.

338, 2038, 12278, 72802, 434174, 2588842, 15426974, 91951882, 548068238, 3266618650, 19470028382, 116047125514, 691674559982, 4122582893626, 24571800071294, 146455111766122, 872915295745934, 5202830428855834

Offset

1,1

Comments

Column 1 of A186052.

Links

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

Formula

Empirical: a(n) = 5*a(n-1) + 4*a(n-2) + 18*a(n-3) - 40*a(n-4) - 24*a(n-5) - 72*a(n-6).

Empirical g.f.: 2*x*(169 + 174*x + 368*x^2 - 1412*x^3 - 1056*x^4 - 2304*x^5) / (1 - 5*x - 4*x^2 - 18*x^3 + 40*x^4 + 24*x^5 + 72*x^6). - Colin Barker, Apr 17 2018

Example

Some solutions for 4 X 3:
..1..1..0....0..0..0....1..1..0....0..1..0....0..0..0....0..0..1....1..1..1
..0..0..0....0..1..0....1..1..0....1..1..0....0..1..1....0..1..1....0..0..0
..0..1..0....0..0..0....1..0..0....0..0..0....0..0..0....0..1..1....1..1..0
..1..1..1....0..0..1....0..1..0....1..0..0....0..0..0....0..0..1....1..1..1

Crossrefs

Cf. A186052.

Sequence in context: A188213 A250802 A186052 * A070311 A205648 A221799

Adjacent sequences: A186041 A186042 A186043 * A186045 A186046 A186047

Keyword

nonn

Author

R. H. Hardin, Feb 11 2011

Status

approved