A230676 Number of 2 X n 0..2 arrays x(i,j) with each element horizontally, diagonally or antidiagonally next to at least one element with value 2-x(i,j).

0, 15, 87, 513, 3387, 21933, 141411, 913245, 5898099, 38088477, 245968275, 1588424445, 10257784563, 66243081501, 427786930899, 2762577674301, 17840272397235, 115209545904477, 744004305214611, 4804657476983421

Offset

1,2

Links

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

Formula

Empirical: a(n) = 5*a(n-1) + 6*a(n-2) + 20*a(n-3) + 12*a(n-4) + 8*a(n-5).

Empirical g.f.: 3*x^2*(5 + 4*x - 4*x^2) / (1 - 5*x - 6*x^2 - 20*x^3 - 12*x^4 - 8*x^5). - Colin Barker, Sep 22 2018

Example

Some solutions for n=3:
..0..2..2....0..0..2....1..1..1....0..2..0....0..0..2....0..2..0....2..2..2
..0..0..0....2..2..2....1..2..0....0..2..0....2..2..0....0..1..1....0..0..2

Crossrefs

Row 2 of A230675.

Sequence in context: A367228 A309922 A302948 * A232070 A219598 A241433

Adjacent sequences: A230673 A230674 A230675 * A230677 A230678 A230679

Keyword

nonn

Author

R. H. Hardin, Oct 27 2013

Status

approved