A317766 Number of nXn 0..1 arrays with every element unequal to 0, 1 or 3 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

1, 3, 5, 10, 19, 40, 75, 159, 310, 600, 1117, 2146, 4102, 7866, 14925, 28415, 54123, 103279, 196740, 374715, 713672, 1359955, 2591227, 4936722, 9404444, 17916937, 34135626, 65035274

Offset

1,2

Comments

Diagonal of A317773.

Links

Table of n, a(n) for n=1..28.

Example

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

Crossrefs

Cf. A317773.

Sequence in context: A014610 A117591 A003055 * A217925 A018101 A298184

Adjacent sequences: A317763 A317764 A317765 * A317767 A317768 A317769

Keyword

nonn

Author

R. H. Hardin, Aug 06 2018

Status

approved