A185459 Number of (n+1) X 2 binary arrays with no 2 X 2 subblock determinant equal to any horizontal or vertical neighbor 2 X 2 subblock determinant.

16, 34, 92, 218, 540, 1320, 3238, 7934, 19450, 47672, 116850, 286412, 702028, 1720746, 4217738, 10338138, 25339908, 62110890, 152240596, 373158376, 914652054, 2241912374, 5495172802, 13469270464, 33014657298, 80922541380

Offset

1,1

Comments

Column 1 of A185467.

Links

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

Formula

Empirical: a(n) = a(n-1) + 2*a(n-2) + 3*a(n-3) + 2*a(n-4) for n>5.

Empirical g.f.: 2*x*(8 + 9*x + 13*x^2 + 5*x^3 + 2*x^4) / (1 - x - 2*x^2 - 3*x^3 - 2*x^4). - Colin Barker, Apr 15 2018

Example

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

Crossrefs

Cf. A185467.

Sequence in context: A209377 A203446 A153819 * A279712 A228800 A230943

Adjacent sequences: A185456 A185457 A185458 * A185460 A185461 A185462

Keyword

nonn

Author

R. H. Hardin, Jan 28 2011

Status

approved