A207854 Number of nX4 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 1 0 and 1 0 1 vertically.

9, 81, 289, 1369, 5929, 26569, 117649, 522729, 2319529, 10297681, 45711121, 202920025, 900780169, 3998665225, 17750499361, 78796419849, 349785896329, 1552737795921, 6892772417281, 30597768825625, 135826834143529

Offset: 1

Author

R. H. Hardin Feb 21 2012

Keywords

• nonn

Comments

Column 4 of A207858

Examples

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

Links

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

Formula

Empirical: a(n) = 4*a(n-1) +a(n-2) +18*a(n-4) +4*a(n-5) -2*a(n-6) -8*a(n-7) -a(n-8) +a(n-10)