A207940 Number of 4Xn 0..1 arrays avoiding 0 0 1 and 1 0 0 horizontally and 0 0 1 and 1 1 0 vertically.

8, 64, 200, 643, 2422, 9430, 38207, 156792, 649758, 2703377, 11276024, 47088326, 196773391, 822559178, 3439147214, 14380613647, 60135069834, 251472698220, 1051624711847, 4397789612658, 18391203655144, 76910735347923

Offset: 1

Author

R. H. Hardin Feb 21 2012

Keywords

• nonn

Comments

Row 4 of A207938

Examples

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

Links

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

Formula

Empirical: a(n) = 7*a(n-1) -6*a(n-2) -42*a(n-3) +62*a(n-4) +91*a(n-5) -149*a(n-6) -91*a(n-7) +138*a(n-8) +42*a(n-9) -50*a(n-10) -7*a(n-11) +6*a(n-12) for n>13