A202464 Number of (n+2) X 3 binary arrays with no more than two of any consecutive three bits set in any row or column.

265, 1573, 9253, 54085, 317179, 1858993, 10894297, 63850777, 374215201, 2193190681, 12853833343, 75333557377, 441513844561, 2587618272973, 15165477047269, 88881616706701, 520916142332515, 3052978074328417

Offset: 1

Author

R. H. Hardin, Dec 19 2011

Keywords

• nonn

Comments

Column 1 of A202471.

Examples

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

Links

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

Crossrefs

Cf. A202471.

Formula

Empirical: a(n) = 4*a(n-1) +8*a(n-2) +18*a(n-3) -6*a(n-4) +2*a(n-5) -a(n-6).

Empirical g.f.: x*(265 + 513*x + 841*x^2 - 281*x^3 + 91*x^4 - 49*x^5) / (1 - 4*x - 8*x^2 - 18*x^3 + 6*x^4 - 2*x^5 + x^6). - Colin Barker, Jun 01 2018