A300343 Number of n X n 0..1 arrays with every element equal to 1 or 2 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

0, 2, 9, 58, 306, 1371, 5451, 20316, 73826, 268227, 988143, 3710046, 14186486, 55056941, 215998713, 853659146, 3389857782, 13500951049, 53867577061

Offset

1,2

Comments

Diagonal of A300350.

Links

Table of n, a(n) for n=1..19.

Example

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

Crossrefs

Cf. A300350.

Sequence in context: A111545 A070075 A124405 * A141787 A047852 A240881

Adjacent sequences: A300340 A300341 A300342 * A300344 A300345 A300346

Keyword

nonn

Author

R. H. Hardin, Mar 03 2018

Status

approved