A210088 Number of (n+1) X 2 0..2 arrays containing all values 0..2 with every 2 X 2 subblock having one or two distinct values, and new values 0..2 introduced in row major order.

0, 9, 90, 657, 4230, 25533, 148410, 842265, 4704750, 25994709, 142528770, 777216177, 4221470070, 22863109293, 123563792970, 666766408905, 3593844532350, 19354295087109, 104165322930450, 560359838547297

Offset

1,2

Comments

Column 1 of A210095.

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 10*a(n-1) - 27*a(n-2) + 10*a(n-3) + 8*a(n-4).

Empirical g.f.: 9*x^2 / ((1 - x)*(1 - 4*x)*(1 - 5*x - 2*x^2)). - Colin Barker, Jul 14 2018

Example

Some solutions for n=4:
..0..0....0..0....0..1....0..0....0..1....0..0....0..0....0..1....0..0....0..1
..1..0....0..0....0..0....1..1....1..1....0..1....0..1....1..1....0..1....0..1
..1..0....0..0....1..0....1..0....0..0....0..0....0..0....1..0....0..0....0..0
..0..0....1..1....0..0....1..1....1..1....0..2....2..0....1..1....0..2....2..0
..0..2....1..2....0..2....1..2....1..2....2..0....0..0....2..1....0..2....2..2

Crossrefs

Cf. A210095.

Sequence in context: A165135 A277105 A180289 * A261315 A270242 A054616

Adjacent sequences: A210085 A210086 A210087 * A210089 A210090 A210091

Keyword

nonn

Author

R. H. Hardin, Mar 17 2012

Status

approved