A221933 Number of n X 3 arrays of occupancy after each element stays put or moves to some horizontal or antidiagonal neighbor, without move-in move-out straight through or left turns.

6, 105, 1599, 24535, 376389, 5773962, 88575493, 1358791848, 20844539836, 319765562424, 4905362062396, 75250682972713, 1154382737872290, 17708802802243865, 271661803663808763, 4167426584055854255

Offset: 1

Author

R. H. Hardin, Feb 01 2013

Keywords

• nonn

Comments

Column 3 of A221937.

Examples

			Some solutions for n=3:
..0..3..1....1..3..0....2..0..1....1..0..1....2..0..1....1..2..0....0..2..1
..0..1..0....0..2..0....1..0..1....2..1..0....2..0..0....0..3..0....0..4..0
..0..3..1....1..2..0....2..2..0....1..3..0....1..2..1....1..0..2....1..0..1
		

Links

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

Crossrefs

Cf. A221937.

Formula

Empirical: a(n) = 14*a(n-1) + 21*a(n-2) - 5*a(n-3) - 26*a(n-4) + a(n-5).

Empirical g.f.: x*(6 + 21*x + 3*x^2 - 26*x^3 + x^4) / (1 - 14*x - 21*x^2 + 5*x^3 + 26*x^4 - x^5). - Colin Barker, Aug 11 2018