A208165 Number of 4Xn 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 0 1 and 0 1 0 vertically.

9, 81, 287, 981, 2920, 9039, 28681, 89623, 278652, 872602, 2730176, 8525256, 26645271, 83307020, 260355204, 813693708, 2543369350, 7949447810, 24845860649, 77657127110, 242721701342, 758634528231, 2371142647768, 7411113488204

Offset: 1

Author

R. H. Hardin Feb 24 2012

Keywords

• nonn

Comments

Row 4 of A208164

Examples

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

Links

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

Formula

Empirical: a(n) = a(n-1) +16*a(n-3) +13*a(n-4) +21*a(n-5) -24*a(n-6) -56*a(n-7) -65*a(n-8) +3*a(n-9) +93*a(n-10) +114*a(n-11) +a(n-12) -99*a(n-13) -107*a(n-14) +14*a(n-15) +86*a(n-16) +39*a(n-17) -34*a(n-18) -19*a(n-19) +6*a(n-21) for n>23