A283124 Number of nX2 0..1 arrays with no 1 equal to more than two of its horizontal and vertical neighbors.

4, 16, 57, 209, 768, 2816, 10329, 37889, 138980, 509792, 1869969, 6859233, 25160352, 92290688, 338531473, 1241767297, 4554926628, 16707926384, 61286344841, 224804441777, 824605173856, 3024734241792, 11095027685417, 40697671100929

Offset

1,1

Comments

Column 2 of A283130.

Links

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

Formula

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

Empirical: G.f.: -x*(x+2)*(x^3-x-2)/(1-3*x-2*x^2-2*x^3+x^4+x^5) . - R. J. Mathar, Mar 02 2017

Example

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

Crossrefs

Cf. A283130.

Sequence in context: A197674 A297220 A297375 * A282393 A034514 A263851

Adjacent sequences: A283121 A283122 A283123 * A283125 A283126 A283127

Keyword

nonn

Author

R. H. Hardin, Mar 01 2017

Status

approved