A207731 Number of 4Xn 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 1 1 and 1 0 1 vertically.

9, 81, 189, 441, 2163, 10609, 33063, 103041, 418263, 1697809, 5875227, 20331081, 77333859, 294156801, 1057136187, 3799119769, 14123193995, 52502848225, 191262879795, 696752470089, 2569117858827, 9473043664561, 34677617171731

Offset: 1

Author

R. H. Hardin Feb 19 2012

Keywords

• nonn

Comments

Row 4 of A207729

Examples

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

Links

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

Formula

Empirical: a(n) = a(n-1) +12*a(n-3) +98*a(n-4) +12*a(n-5) +34*a(n-6) -230*a(n-7) -1980*a(n-8) -508*a(n-9) +340*a(n-10) +840*a(n-11) +9800*a(n-12) +3000*a(n-13) +2000*a(n-15) -10000*a(n-16)