A183684 Number of (n+1) X 6 binary arrays with every 2 X 2 subblock nonsingular.

96, 528, 2688, 14144, 73344, 382848, 1992320, 10382976, 54072960, 281700992, 1467309696, 7643513472, 39814841984, 207399103104, 1080347897472, 5627597738624, 29314404685440, 152700279978624, 795423120883328

Offset

1,1

Comments

Column 5 of A183688.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) + 18*a(n-2) - 20*a(n-3) - 72*a(n-4).

Empirical g.f.: 16*x*(6 + 15*x - 39*x^2 - 94*x^3) / ((1 + 2*x)*(1 - 5*x - 8*x^2 + 36*x^3)). - Colin Barker, Apr 04 2018

Example

Some solutions for 3 X 6:
..0..1..1..0..1..0....1..0..1..1..0..1....0..1..0..1..0..1....1..1..0..1..1..0
..1..0..1..1..1..1....0..1..0..1..1..0....1..1..1..1..1..0....1..0..1..0..1..1
..0..1..1..0..1..0....1..0..1..0..1..1....0..1..0..1..0..1....0..1..1..1..1..0

Crossrefs

Cf. A183688.

Sequence in context: A234076 A337303 A216372 * A251167 A251160 A233029

Adjacent sequences: A183681 A183682 A183683 * A183685 A183686 A183687

Keyword

nonn

Author

R. H. Hardin, Jan 06 2011

Status

approved