A209041 Number of n X 2 0..3 arrays with no element equal the average of immediate neighbors vertically above and horizontally left of it.

12, 124, 1300, 13644, 143212, 1503212, 15778340, 165616044, 1738375148, 18246711388, 191525101396, 2010327432972, 21101236121548, 221487384867980, 2324824070641124, 24402324144347820, 256136983080016460

Offset: 1

Author

R. H. Hardin, Mar 04 2012

Keywords

• nonn

Comments

Column 2 of A209047.

Examples

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

Links

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

Crossrefs

Cf. A209047.

Formula

Empirical: a(n) = 11*a(n-1) - 5*a(n-2) - 3*a(n-3).

Empirical g.f.: 4*x*(1 - x)*(3 + x) / (1 - 11*x + 5*x^2 + 3*x^3). - Colin Barker, Jul 08 2018