A301945 Number of n X n 0..1 arrays with every element equal to 1, 2 or 3 horizontally or antidiagonally adjacent elements, with upper left element zero.

0, 2, 20, 947, 120815, 58609226, 86143630040, 418568449327270, 6527100767589040926, 331808147283786972146018, 54543586667142977292165721500, 29084806316831133817614992597097070

Offset

1,2

Comments

Diagonal of A301951.

Links

R. H. Hardin, Table of n, a(n) for n = 1..13

Example

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

Crossrefs

Cf. A301951.

Sequence in context: A006547 A290883 A135757 * A158843 A008793 A361297

Adjacent sequences: A301942 A301943 A301944 * A301946 A301947 A301948

Keyword

nonn

Author

R. H. Hardin, Mar 29 2018

Status

approved