A301818 Number of n X n 0..1 arrays with every element equal to 1 or 2 horizontally or antidiagonally adjacent elements, with upper left element zero.

0, 2, 4, 68, 1197, 31061, 2341241, 221373169, 47059520355, 17662862033686, 11449618914826511, 15088557751754929900, 33289512591289837483184, 143748055903459113756507351, 1108648718940092116466729395935

Offset

1,2

Comments

Diagonal of A301823.

Links

R. H. Hardin, Table of n, a(n) for n = 1..16

Example

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

Crossrefs

Cf. A301823.

Sequence in context: A018364 A100603 A362456 * A054920 A062061 A066974

Adjacent sequences: A301815 A301816 A301817 * A301819 A301820 A301821

Keyword

nonn

Author

R. H. Hardin, Mar 27 2018

Status

approved