A233068 Number of n X 3 0..3 arrays with no element x(i,j) adjacent to value 3-x(i,j) horizontally, antidiagonally or vertically, top left element zero, and 1 appearing before 2 in row major order.

5, 50, 582, 6854, 80811, 952869, 11235652, 132484030, 1562171807, 18420188169, 217199754056, 2561088558394, 30198812298187, 356086188910685, 4198753668883532, 49509171995392534, 583782308982449751

Offset: 1

Author

R. H. Hardin, Dec 03 2013

Keywords

• nonn

Examples

			Some solutions for n=5:
..0..0..1....0..1..1....0..1..0....0..0..1....0..1..3....0..1..0....0..1..1
..0..0..1....1..1..3....1..1..0....1..0..0....1..3..1....1..1..1....1..0..1
..0..0..0....3..3..1....1..0..0....1..0..2....3..3..3....3..3..1....0..1..1
..2..2..2....1..1..1....1..0..1....0..2..2....3..2..2....3..3..1....1..3..3
..3..2..3....3..1..0....1..0..0....0..2..3....2..3..2....3..3..3....3..3..2
		

Links

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

Crossrefs

Column 3 of A233073.

Formula

Empirical: a(n) = 14*a(n-1) - 28*a(n-2) + 24*a(n-3) - 11*a(n-4) + 2*a(n-5) for n>6.

Empirical g.f.: x*(5 - 20*x + 22*x^2 - 14*x^3 + 6*x^4 - x^5) / ((1 - x)*(1 - 13*x + 15*x^2 - 9*x^3 + 2*x^4)). - Colin Barker, Oct 07 2018