A210383 Number of (n+1) X 2 0..2 arrays with every 2 X 2 subblock having one, two or three distinct clockwise edge differences.

73, 597, 4881, 39909, 326313, 2668077, 21815361, 178371909, 1458446553, 11924895357, 97503147441, 797228275509, 6518486222793, 53297987467437, 435787600217121, 3563189559812709, 29134192512207033, 238213869649684317

Offset

1,1

Comments

Column 1 of A210390.

Links

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

Formula

Empirical: a(n) = 9*a(n-1) - 6*a(n-2) - 6*a(n-3).

Empirical g.f.: x*(73 - 60*x - 54*x^2) / (1 - 9*x + 6*x^2 + 6*x^3). - Colin Barker, Jul 15 2018

Example

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

Crossrefs

Cf. A210390.

Sequence in context: A235465 A201263 A210390 * A142675 A167187 A177095

Adjacent sequences: A210380 A210381 A210382 * A210384 A210385 A210386

Keyword

nonn

Author

R. H. Hardin, Mar 20 2012

Status

approved