A155254 Number of ways to place zero or more nonadjacent 1,0 2,0 2,1 2,2 3,0 4,0 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 7, 25, 76, 295, 1744, 13870, 129297, 1393351, 18761115, 322004760, 6998296402, 187297012609

Offset

4,2

Links

Table of n, a(n) for n=4..16.

Example

Maximal 11 X 11 X 11 example
.............1
............1.0
...........1.0.1
..........1.1.0.1
.........0.0.1.0.1
........1.0.0.0.1.1
.......1.1.1.0.1.0.0
......1.0.0.0.0.0.0.1
.....1.0.1.0.1.0.1.1.1
....0.0.1.0.0.1.0.0.0.1
...1.1.1.1.0.1.1.1.1.0.1

Crossrefs

Sequence in context: A294837 A117152 A155281 * A155295 A168589 A058481

Adjacent sequences: A155251 A155252 A155253 * A155255 A155256 A155257

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved