A155226 Number of ways to place zero or more nonadjacent 0,0 1,0 2,1 3,1 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 7, 19, 58, 329, 2350, 20015, 218371, 3090717, 58164789, 1393078738, 42785732400, 1703751776933, 87700729777393, 5826804979644472

Offset

3,2

Links

Table of n, a(n) for n=3..17.

Example

Maximal 11 X 11 X 11 example
.............0
............1.0
...........0.1.1
..........1.0.0.1
.........1.0.0.0.0
........0.1.0.0.1.1
.......0.1.0.1.1.0.0
......1.0.0.0.0.0.1.1
.....1.0.1.0.0.1.1.0.0
....0.1.0.1.1.0.0.0.1.1
...0.1.0.0.0.1.0.1.1.0.0

Crossrefs

Sequence in context: A000413 A263335 A155335 * A229442 A179406 A165683

Adjacent sequences: A155223 A155224 A155225 * A155227 A155228 A155229

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved