A267899 Number of nX3 arrays containing 3 copies of 0..n-1 with every element equal to at least one horizontal or vertical neighbor and the top left element equal to 0.

1, 3, 20, 138, 1488, 20400, 317520, 5911920, 126080640, 2999566080, 79604985600

Offset

1,2

Comments

Column 3 of A267901.

Links

Table of n, a(n) for n=1..11.

Example

Some solutions for n=4
..0..0..1....0..0..0....0..0..0....0..0..1....0..1..1....0..0..3....0..2..2
..0..1..1....2..3..3....1..1..1....2..0..1....0..1..2....0..3..3....0..0..2
..2..2..3....2..3..1....2..2..2....2..2..1....0..2..2....1..1..1....3..1..1
..2..3..3....2..1..1....3..3..3....3..3..3....3..3..3....2..2..2....3..3..1

Crossrefs

Cf. A267901.

Sequence in context: A056298 A114479 A074574 * A073514 A163065 A082143

Adjacent sequences: A267896 A267897 A267898 * A267900 A267901 A267902

Keyword

nonn

Author

R. H. Hardin, Jan 22 2016

Status

approved