A241133 Number of n X 2 0..2 arrays with no element equal to the same number of vertical neighbors as horizontal neighbors, with new values 0..2 introduced in row major order.

1, 2, 5, 17, 56, 195, 691, 2476, 8941, 32393, 117632, 427635, 1555643, 5661060, 20604893, 75004865, 273044808, 994013923, 3618750915, 13174348572, 47962513037, 174612764153, 635697854288, 2314333217939, 8425607885003

Offset: 1

Author

R. H. Hardin, Apr 16 2014

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Column 2 of A241138.

Formula

Empirical: a(n) = 4*a(n-1) + 2*a(n-2) - 11*a(n-3) - 6*a(n-4) + 8*a(n-5) for n>6.

Empirical g.f.: x*(1 - x)*(1 - x - 6*x^2 - 2*x^3 + 4*x^4) / ((1 - 2*x)*(1 - 2*x - 6*x^2 - x^3 + 4*x^4)). - Colin Barker, Oct 29 2018