A232042 Number of n X 3 0..1 arrays with no element less than a strict majority of its horizontal and antidiagonal neighbors.

4, 15, 80, 446, 2477, 13752, 76375, 424115, 2355221, 13079032, 72630752, 403334385, 2239803950, 12438120321, 69071597937, 383569664377, 2130046094920, 11828611039210, 65686859759121, 364773474308192, 2025666747456127

Offset

1,1

Links

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

Formula

Empirical: a(n) = 4*a(n-1) + 9*a(n-2) -a (n-3) - 6*a(n-4) for n>5.

Empirical g.f.: x*(4 - x - 16*x^2 - 5*x^3 + 12*x^4) / (1 - 4*x - 9*x^2 + x^3 + 6*x^4). - Colin Barker, Oct 02 2018

Example

Some solutions for n=7:
..1..1..0....1..1..0....0..0..1....1..1..0....1..0..0....1..1..1....1..1..0
..0..0..0....1..0..0....0..1..0....0..0..0....0..0..0....1..0..0....0..0..0
..1..1..0....1..1..1....1..0..0....0..1..0....0..0..0....0..1..0....0..0..0
..1..0..1....0..0..0....1..0..0....0..0..0....1..0..1....0..0..0....0..0..0
..0..1..0....0..0..0....0..1..0....1..1..1....0..1..1....1..0..0....1..1..1
..0..0..0....1..0..1....0..0..0....0..0..0....0..0..0....1..1..1....0..0..1
..0..0..0....0..1..1....0..0..1....1..0..0....0..0..0....0..0..0....0..1..1

Crossrefs

Column 3 of A232047.

Sequence in context: A179511 A111726 A090376 * A125307 A073479 A147690

Adjacent sequences: A232039 A232040 A232041 * A232043 A232044 A232045

Keyword

nonn

Author

R. H. Hardin, Nov 17 2013

Status

approved