A282641 Number of nX2 0..1 arrays with no 1 equal to more than one of its king-move neighbors.

4, 11, 27, 76, 201, 537, 1444, 3859, 10339, 27692, 74145, 198577, 531780, 1424091, 3813739, 10213132, 27350713, 73245065, 196149732, 525287779, 1406717235, 3767179500, 10088482321, 27016889761, 72351054724, 193755653291

Offset: 1

Author

R. H. Hardin, Feb 20 2017

Keywords

• nonn

Comments

Column 2 of A282647.

Examples

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

Links

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

Crossrefs

Cf. A282647.

Formula

Empirical: a(n) = a(n-1) +3*a(n-2) +4*a(n-3).

G.f.: -x*(4+7*x+4*x^2)/(-1+x+3*x^2+4*x^3) . - R. J. Mathar, Feb 28 2017