A208439 Number of n X 2 0..2 arrays with no element equal the average of immediate neighbors vertically above and horizontally left of it.

6, 28, 134, 646, 3118, 15052, 72662, 350776, 1693360, 8174678, 39463082, 190507418, 919671000, 4439696150, 21432553756, 103465280456, 499476814534, 2411215573070, 11640100762206, 56192382129180, 271267737270734

Offset

1,1

Comments

Column 2 of A208445.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) + 10*a(n-2) - 7*a(n-3) + 8*a(n-4) - 8*a(n-5).

Empirical g.f.: 2*x*(1 - x)*(3 + 8*x + 3*x^2 + 6*x^3) / (1 - 3*x - 10*x^2 + 7*x^3 - 8*x^4 + 8*x^5). - Colin Barker, Jul 03 2018

Example

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

Crossrefs

Cf. A208445.

Sequence in context: A155588 A368574 A373929 * A108051 A199315 A001599

Adjacent sequences: A208436 A208437 A208438 * A208440 A208441 A208442

Keyword

nonn

Author

R. H. Hardin, Feb 26 2012

Status

approved