A207392 Number of 3Xn 0..1 arrays avoiding 0 0 1 and 0 1 0 horizontally and 0 0 1 and 1 1 0 vertically.

6, 36, 98, 271, 834, 2307, 6115, 16544, 44250, 116526, 307117, 808976, 2122787, 5564987, 14588870, 38216326, 100064540, 261992129, 685862456, 1795255303, 4698927663, 12298716264, 32188880680, 84245176534, 220486127041

Offset: 1

Author

R. H. Hardin Feb 17 2012

Keywords

• nonn

Comments

Row 3 of A207391

Examples

			Some solutions for n=4
..1..0..0..0....1..1..1..1....1..1..1..1....0..0..0..0....0..0..0..0
..1..0..1..1....0..0..0..0....1..1..1..1....0..1..1..1....0..1..1..0
..1..0..1..1....0..1..1..1....1..1..1..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) = 3*a(n-1) -2*a(n-2) +9*a(n-3) -15*a(n-4) -21*a(n-6) +16*a(n-7) +11*a(n-8) +27*a(n-9) +2*a(n-10) -12*a(n-12) -a(n-13) -2*a(n-14) +2*a(n-15)