A207113 Number of 4Xn 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 1 1 0 vertically.

8, 64, 200, 643, 1835, 4534, 11511, 27012, 62814, 144676, 325111, 733469, 1635998, 3639007, 8091148, 17910532, 39681294, 87775953, 194044225, 429056388, 947971827, 2094875648, 4628499152, 10225059546, 22590584639, 49903794405

Offset: 1

Author

R. H. Hardin Feb 15 2012

Keywords

• nonn

Comments

Row 4 of A207111

Examples

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

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +5*a(n-2) -4*a(n-3) -23*a(n-4) +4*a(n-5) +40*a(n-6) +19*a(n-7) -38*a(n-8) -28*a(n-9) -a(n-11) +13*a(n-12) +38*a(n-13) +15*a(n-14) -31*a(n-15) -24*a(n-16) -2*a(n-17) +9*a(n-18) +6*a(n-19) +6*a(n-20) -2*a(n-21) -3*a(n-22) -a(n-23) +a(n-24)