A268621 Number of n X n 0..2 arrays with some element plus some horizontally or vertically adjacent neighbor totaling two no more than once.

3, 42, 1086, 55452, 6000978, 1430057208, 767057092212, 938662461734076, 2643885168776274078, 17245474696462104041796, 261641272761781630830646332, 9262823664147270920479995625968, 767111588793900754143144516979246884

Offset

1,1

Comments

Diagonal of A268628.

Links

R. H. Hardin, Table of n, a(n) for n = 1..14

Example

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

Crossrefs

Cf. A268628.

Sequence in context: A206820 A157542 A078601 * A218308 A195010 A333323

Adjacent sequences: A268618 A268619 A268620 * A268622 A268623 A268624

Keyword

nonn

Author

R. H. Hardin, Feb 09 2016

Status

approved