A155423 Number of ways to place zero or more nonadjacent 0,0 1,0 2,1 3,1 4,2 5,2 6,3 7,3 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 7, 19, 52, 172, 643, 2936, 14954, 84090, 537490, 4238593, 38671134

Offset

7,2

Links

Table of n, a(n) for n=7..18.

Example

Maximal 10 X 10 X 10 example
............0
...........0.0
..........1.0.1
.........1.0.0.1
........0.1.0.1.0
.......0.1.0.0.1.0
......0.0.1.0.1.0.0
.....0.0.1.0.0.1.0.0
....0.0.0.1.0.1.0.0.0
...0.0.0.1.0.0.1.0.0.0

Crossrefs

Sequence in context: A203165 A332364 A100450 * A155347 A155385 A155345

Adjacent sequences: A155420 A155421 A155422 * A155424 A155425 A155426

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved