A155416 Number of ways to place zero or more nonadjacent 0,0 1,0 2,1 3,1 3,2 4,2 5,2 6,3 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 7, 19, 37, 103, 427, 2239, 11637, 57017, 383473, 3234253, 30969391, 316348867

Offset

6,2

Links

Table of n, a(n) for n=6..18.

Example

Maximal 11 X 11 X 11 example
.............0
............0.0
...........0.0.0
..........1.1.0.0
.........0.0.1.1.0
........0.0.0.1.1.1
.......0.0.0.0.0.0.1
......1.1.0.0.1.1.0.0
.....0.0.1.1.0.0.1.1.0
....0.0.0.1.1.1.0.1.1.1
...0.0.0.0.0.0.1.0.0.0.1

Crossrefs

Sequence in context: A155379 A155243 A155417 * A155391 A155400 A155359

Adjacent sequences: A155413 A155414 A155415 * A155417 A155418 A155419

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved