A221323 Number of n X 3 arrays of occupancy after each element stays put or moves to some horizontal or antidiagonal neighbor, with no occupancy greater than 2.

7, 119, 2008, 33873, 571358, 9637322, 162555929, 2741882383, 46248186229, 780082534460, 13157894317753, 221938287447408, 3743501973486176, 63142809559541159, 1065049364666447387, 17964518161956501475

Offset: 1

Author

R. H. Hardin, Jan 11 2013

Keywords

• nonn

Comments

Column 3 of A221328.

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..69

Crossrefs

Cf. A221328.

Formula

Empirical: a(n) = 23*a(n-1) - 110*a(n-2) + 111*a(n-3) - 6*a(n-4) - 8*a(n-5).

Empirical g.f.: x*(1 - x)*(7 - 35*x + 6*x^2 + 8*x^3) / (1 - 23*x + 110*x^2 - 111*x^3 + 6*x^4 + 8*x^5). - Colin Barker, Aug 05 2018