A205468 Number of (n+1) X 2 0..2 arrays with every 2 X 2 subblock having the same number of equal edges, and new values 0..2 introduced in row major order.

14, 48, 175, 677, 2709, 11143, 46709, 198483, 851317, 3674723, 15929949, 69254347, 301652741, 1315582371, 5742416845, 25079258843, 109571246421, 478835560339, 2092898539805, 9148671997707, 39994487184037, 174849254952131

Offset: 1

Author

R. H. Hardin, Jan 27 2012

Keywords

• nonn

Comments

Column 1 of A205475.

Examples

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

Links

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

Crossrefs

Cf. A205475.

Formula

Empirical: a(n) = 9*a(n-1) - 21*a(n-2) - 11*a(n-3) + 66*a(n-4) - 6*a(n-5) - 36*a(n-6).

Empirical g.f.: x*(14 - 78*x + 37*x^2 + 264*x^3 - 105*x^4 - 180*x^5) / ((1 - x)*(1 - 3*x)*(1 - 2*x - 2*x^2)*(1 - 3*x - 6*x^2)). - Colin Barker, Mar 04 2018