A301879 Number of nX3 0..1 arrays with every element equal to 0, 1 or 3 horizontally or antidiagonally adjacent elements, with upper left element zero.

3, 10, 29, 95, 289, 917, 2841, 8921, 27801, 87009, 271657, 849313, 2653273, 8292465, 25910729, 80972065, 253021369, 790675217, 2470747561, 7720841601, 24126677401, 75393222129, 235594969737, 736207657313, 2300563919993, 7188999803345

Offset

1,1

Comments

Column 3 of A301884.

Links

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

Formula

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

Example

Some solutions for n=5
..0..1..0. .0..1..0. .0..1..0. .0..1..0. .0..1..0. .0..0..0. .0..1..0
..0..0..1. .0..0..0. .1..0..1. .0..1..0. .0..1..1. .0..1..1. .0..1..0
..0..1..0. .1..1..0. .1..0..1. .0..1..0. .0..0..0. .0..0..1. .1..0..0
..0..1..0. .0..1..0. .1..0..1. .1..0..0. .0..1..1. .1..0..1. .0..1..1
..0..1..0. .1..0..1. .1..0..1. .0..1..1. .0..0..1. .1..0..1. .0..0..1

Crossrefs

Cf. A301884.

Sequence in context: A361365 A147363 A147226 * A147062 A293155 A146384

Adjacent sequences: A301876 A301877 A301878 * A301880 A301881 A301882

Keyword

nonn

Author

R. H. Hardin, Mar 28 2018

Status

approved