A155235 Number of ways to place zero or more nonadjacent 0,0 1,0 2,0 2,1 3,0 polyhexes in any orientation on a planar n X n X n triangular grid.

1, 4, 13, 37, 152, 704, 5022, 42621, 420222, 5313446, 83504848, 1668949583, 41600395450, 1285489016880, 49769130940759

Offset

3,2

Links

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

Example

Maximal 13 X 13 X 13 example
...............1
..............1.0
.............1.1.0
............1.0.0.1
...........0.0.0.0.1
..........0.1.0.0.1.1
.........1.0.1.0.0.0.1
........1.0.1.1.0.1.0.0
.......1.1.0.0.1.0.1.1.0
......1.0.0.0.0.0.0.1.0.1
.....0.0.1.1.1.1.0.0.1.0.1
....0.1.0.0.1.0.0.1.0.0.1.1
...1.1.1.1.0.0.1.1.1.1.0.0.1

Crossrefs

Sequence in context: A155307 A155344 A155418 * A024450 A047094 A145128

Adjacent sequences: A155232 A155233 A155234 * A155236 A155237 A155238

Keyword

nonn

Author

R. H. Hardin, Jan 22 2009

Status

approved