A208170 Number of n X 3 0..3 arrays with new values 0..3 introduced in row major order and no element equal to more than one of its immediate leftward or upward neighbors.

5, 159, 8469, 473928, 26625693, 1496307201, 84091222866, 4725865313907, 265590215430897, 14925978329967384, 838829205068709369, 47141595663874099773, 2649323638611897879018, 148890075596000256587991

Offset: 1

Author

R. H. Hardin, Feb 24 2012

Keywords

• nonn

Comments

Column 3 of A208175.

Examples

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

Links

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

Crossrefs

Cf. A208175.

Formula

Empirical: a(n) = 62*a(n-1) - 333*a(n-2) + 396*a(n-3) - 135*a(n-4) for n>5.

Empirical g.f.: x*(5 - 151*x + 276*x^2 - 183*x^3 + 45*x^4) / ((1 - 5*x + 3*x^2)*(1 - 57*x + 45*x^2)). - Colin Barker, Jun 29 2018