A207307 Number of 4Xn 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 0 1 and 1 1 0 vertically.

8, 64, 200, 643, 1759, 4939, 14446, 41505, 118266, 339548, 975493, 2795633, 8015023, 22994104, 65948845, 189120690, 542403026, 1555646545, 4461518045, 12795484071, 36697414724, 105247642363, 301847990088, 865695191094, 2482800552095

Offset: 1

Author

R. H. Hardin Feb 16 2012

Keywords

• nonn

Comments

Row 4 of A207305

Examples

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

Links

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

Formula

Empirical: a(n) = a(n-1) +2*a(n-2) +8*a(n-3) +7*a(n-4) -2*a(n-5) -10*a(n-6) -10*a(n-7) -a(n-8) +3*a(n-9) +4*a(n-10) +a(n-11) -a(n-13) for n>14