A283858 Number of 2 X n 0..1 arrays with no 1 equal to more than three of its horizontal, diagonal and antidiagonal neighbors.

4, 16, 61, 233, 896, 3444, 13225, 50789, 195076, 749256, 2877717, 11052673, 42450984, 163045180, 626221537, 2405182717, 9237791852, 35480380112, 136272540429, 523393640665, 2010242874320, 7720912327300, 29654370583449

Offset

1,1

Links

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

Formula

Empirical: a(n) = 3*a(n-1) + a(n-2) + 7*a(n-3) + 6*a(n-4).

Empirical g.f.: x*(4 + 4*x + 9*x^2 + 6*x^3) / (1 - 3*x - x^2 - 7*x^3 - 6*x^4). - Colin Barker, Feb 22 2019

Example

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

Crossrefs

Row 2 of A283857.

Sequence in context: A103820 A206570 A206790 * A283409 A192468 A364921

Adjacent sequences: A283855 A283856 A283857 * A283859 A283860 A283861

Keyword

nonn

Author

R. H. Hardin, Mar 17 2017

Status

approved