A199239 Number of n X n 0..2 arrays with values 0..2 introduced in row major order, the number of instances of each value within one of each other, and every element equal to zero or two horizontal or vertical neighbors

1, 2, 6, 440, 29227, 1682457, 2013526831

Offset

1,2

Comments

Diagonal of A199246

Links

Table of n, a(n) for n=1..7.

Example

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

Crossrefs

Sequence in context: A252741 A069261 A053608 * A123261 A124061 A354516

Adjacent sequences: A199236 A199237 A199238 * A199240 A199241 A199242

Keyword

nonn

Author

R. H. Hardin Nov 04 2011

Status

approved