A301959 Number of nX3 0..1 arrays with every element equal to 0, 1 or 4 horizontally or antidiagonally adjacent elements, with upper left element zero.

3, 6, 16, 40, 100, 252, 632, 1588, 3988, 10016, 25156, 63180, 158680, 398532, 1000932, 2513888, 6313748, 15857276, 39826296, 100025620, 251219060, 630948512, 1584656932, 3979940588, 9995808408, 25104944036, 63052250436, 158358699360

Offset

1,1

Comments

Column 3 of A301964.

Links

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

Formula

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

Example

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

Crossrefs

Cf. A301964.

Sequence in context: A046211 A239980 A205770 * A018022 A166536 A128720

Adjacent sequences: A301956 A301957 A301958 * A301960 A301961 A301962

Keyword

nonn

Author

R. H. Hardin, Mar 29 2018

Status

approved