A208040 Number of 4 X n 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 0 0 and 1 0 1 vertically.

9, 81, 279, 961, 4743, 23409, 100215, 429025, 1942075, 8791225, 38933415, 172423161, 770225067, 3440643649, 15317395695, 68191488225, 303989603715, 1355149763881, 6037892299063, 26901929503849, 119887169037291

Offset: 1

Author

R. H. Hardin, Feb 22 2012

Keywords

• nonn

Comments

Row 4 of A208039.

Examples

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

Links

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

Crossrefs

Cf. A208039.

Formula

Empirical: a(n) = 2*a(n-1) +24*a(n-3) +117*a(n-4) +10*a(n-5) +88*a(n-6) -540*a(n-7) -2784*a(n-8) -648*a(n-9) +880*a(n-10) +2080*a(n-11) +11700*a(n-12) +4200*a(n-13) +2000*a(n-15) -10000*a(n-16).