A282310 Number of n X 2 0..1 arrays with no 1 equal to more than four of its king-move neighbors.

4, 16, 63, 249, 984, 3888, 15363, 60705, 239868, 947808, 3745143, 14798457, 58474224, 231053472, 912978459, 3607518465, 14254651188, 56325444336, 222562841967, 879428812473, 3474951296328, 13730828852304, 54255626883315

Offset

1,1

Links

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

Formula

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

Empirical g.f.: x*(4 + 4*x + 3*x^2) / (1 - 3*x - 3*x^2 - 3*x^3). - Colin Barker, Feb 20 2019

Example

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

Crossrefs

Column 2 of A282316.

Sequence in context: A257838 A099503 A119376 * A022030 A135450 A265032

Adjacent sequences: A282307 A282308 A282309 * A282311 A282312 A282313

Keyword

nonn

Author

R. H. Hardin, Feb 11 2017

Status

approved