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

1,1

Comments

Column 1 of A202471.

Links

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

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

Example

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

Crossrefs

Cf. A202471.

Sequence in context: A259741 A202416 A202471 * A183247 A094795 A023043

Adjacent sequences: A202461 A202462 A202463 * A202465 A202466 A202467

Keyword

nonn

Author

R. H. Hardin, Dec 19 2011

Status

approved