A207404 Number of 4Xn 0..1 arrays avoiding 0 0 1 and 0 1 1 horizontally and 0 0 1 and 1 1 0 vertically.

8, 64, 216, 729, 1782, 4356, 8910, 18225, 33210, 60516, 101598, 170569, 269276, 425104, 639612, 962361, 1393020, 2016400, 2827220, 3964081, 5411538, 7387524, 9858186, 13155129, 17213742, 22524516, 28974330, 37271025, 47228280, 59845696

Offset: 1

Author

R. H. Hardin Feb 17 2012

Keywords

• nonn

Comments

Row 4 of A207403

Examples

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

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +6*a(n-2) -14*a(n-3) -14*a(n-4) +42*a(n-5) +14*a(n-6) -70*a(n-7) +70*a(n-9) -14*a(n-10) -42*a(n-11) +14*a(n-12) +14*a(n-13) -6*a(n-14) -2*a(n-15) +a(n-16)