A207414 Number of nX3 0..1 arrays avoiding 0 0 1 and 0 1 0 horizontally and 0 1 1 and 1 0 1 vertically.

6, 36, 92, 241, 720, 1889, 4719, 12102, 30414, 74588, 182737, 445468, 1075185, 2583413, 6187826, 14753420, 35052328, 83069841, 196345572, 462972905, 1089545883, 2559508250, 6002666694, 14057272936, 32876868289, 76799290072

Offset: 1

Author

R. H. Hardin Feb 17 2012

Keywords

• nonn

Comments

Column 3 of A207419

Examples

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

Links

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

Formula

Empirical: a(n) = 4*a(n-1) -4*a(n-2) +7*a(n-3) -21*a(n-4) +7*a(n-5) -a(n-6) +33*a(n-7) +7*a(n-8) -13*a(n-9) -35*a(n-10) -7*a(n-11) +9*a(n-12) +17*a(n-13) +4*a(n-14) -3*a(n-15) -3*a(n-16)