A232018 Number of n X 3 0..2 arrays with no element less than a strict majority of its horizontal and antidiagonal neighbors.

9, 66, 852, 11517, 156913, 2125749, 28852936, 391447970, 5311170384, 72061691152, 977727048997, 13265735926493, 179988561188366, 2442072186590951, 33133863936280024, 449557939142907661, 6099570552966630306

Offset: 1

Author

R. H. Hardin, Nov 17 2013

Keywords

• nonn

Examples

			Some solutions for n=5:
..1..1..1....0..0..0....2..0..0....2..0..0....1..1..1....1..1..0....0..0..2
..0..0..0....1..0..0....0..0..0....0..2..2....0..0..0....1..0..2....0..0..1
..0..0..0....0..0..0....1..2..1....0..0..1....0..2..1....0..0..2....0..2..2
..2..0..1....0..2..0....1..1..0....0..0..0....0..0..0....0..0..0....2..1..1
..0..0..0....0..0..0....0..0..2....2..0..0....1..0..0....1..0..0....1..1..2
		

Links

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

Crossrefs

Column 3 of A232023.

Formula

Empirical: a(n) = 9*a(n-1) + 59*a(n-2) + 62*a(n-3) - 275*a(n-4) - 257*a(n-5) + 146*a(n-6) + 84*a(n-7) for n>8.

Empirical g.f.: x*(9 - 15*x - 273*x^2 - 603*x^3 + 1375*x^4 + 1668*x^5 - 778*x^6 - 504*x^7) / (1 - 9*x - 59*x^2 - 62*x^3 + 275*x^4 + 257*x^5 - 146*x^6 - 84*x^7). - Colin Barker, Oct 01 2018