A184765 Number of (n+1) X 2 0..3 arrays with every 2 X 2 subblock singular.

64, 424, 2248, 13096, 73288, 417256, 2358280, 13370536, 75704776, 428889448, 2429192584, 13760163880, 77941013320, 441485755624, 2500712951560, 14164866483112, 80234377893064, 454473710492776, 2574286780013704

Offset

1,1

Comments

Column 1 of A184773.

Links

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

Formula

Empirical: a(n) = 5*a(n-1) + 8*a(n-2) - 24*a(n-3).

Empirical g.f.: 8*x*(8 + 13*x - 48*x^2) / (1 - 5*x - 8*x^2 + 24*x^3). - Colin Barker, Apr 14 2018

Example

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

Crossrefs

Cf. A184773.

Sequence in context: A343724 A231841 A184773 * A303799 A305244 A304478

Adjacent sequences: A184762 A184763 A184764 * A184766 A184767 A184768

Keyword

nonn

Author

R. H. Hardin, Jan 21 2011

Status

approved