A268964 Number of n X n 0..2 arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two not more than once.

3, 60, 2016, 136080, 18852912, 5712070032, 3870355944960, 5963413766987592, 21098726553552173712, 172587783760354579099176, 3279749300107885644432555744, 145303202175464965696103410891992

Offset: 1

Author

R. H. Hardin, Feb 16 2016

Keywords

• nonn

Comments

Diagonal of A268971.

Examples

			Some solutions for n=4
..0..1..0..1. .1..0..0..1. .1..2..0..0. .2..1..2..2. .0..1..0..0
..0..1..0..0. .1..0..2..1. .1..0..1..2. .2..1..2..1. .2..1..1..0
..2..1..0..0. .1..2..2..1. .1..0..1..2. .2..2..2..1. .0..0..1..0
..2..1..1..0. .2..2..2..2. .1..0..1..0. .1..1..2..1. .0..0..1..0
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..15

Crossrefs

Cf. A268971.