A232017 Number of n X 2 0..2 arrays with no element less than a strict majority of its horizontal and antidiagonal neighbors.

3, 22, 121, 704, 4059, 23422, 135166, 779977, 4500958, 25973244, 149881402, 864906711, 4991036946, 28801314179, 166201073269, 959081123649, 5534480515641, 31937313562863, 184297694197368, 1063509616098391

Offset

1,1

Links

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

Formula

Empirical: a(n) = 3*a(n-1) + 13*a(n-2) + 16*a(n-3) + 7*a(n-4) + a(n-5).

Empirical g.f.: x*(1 + x)*(3 + x)*(1 + 3*x + x^2) / (1 - 3*x - 13*x^2 - 16*x^3 - 7*x^4 - x^5). - Colin Barker, Oct 01 2018

Example

Some solutions for n=7:
..1..1....2..0....1..1....1..1....0..0....0..0....2..0....2..0....1..1....1..0
..1..0....0..0....0..0....0..0....1..0....0..0....0..1....0..0....1..2....0..1
..0..1....0..1....2..1....1..2....0..0....1..1....2..2....1..2....0..0....1..1
..0..0....2..0....0..0....1..1....1..2....2..2....0..0....1..1....1..1....2..0
..0..1....0..0....0..0....0..0....2..2....2..2....1..1....2..1....2..1....0..1
..2..0....1..1....0..2....0..0....2..1....1..0....1..0....0..0....1..1....0..0
..0..1....1..1....2..2....2..2....1..1....0..2....0..2....1..1....1..1....2..2

Crossrefs

Column 2 of A232023.

Sequence in context: A061182 A143552 A006283 * A100511 A033506 A091639

Adjacent sequences: A232014 A232015 A232016 * A232018 A232019 A232020

Keyword

nonn

Author

R. H. Hardin, Nov 17 2013

Status

approved