A155306 Number of ways to place zero or more nonadjacent 1,0 2,0 3,1 3,2 4,3 4,4 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 7, 25, 55, 208, 1168, 8750, 74240, 701683, 8051955, 120548805, 2289918377, 52736906771

Offset

4,2

Links

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

Example

Maximal 11 X 11 X 11 example
.............0
............0.0
...........0.0.0
..........1.1.0.1
.........1.0.0.0.1
........0.1.0.0.1.0
.......0.1.0.0.0.1.0
......0.0.1.0.1.1.0.1
.....1.0.0.0.0.0.0.0.1
....0.1.1.0.1.0.0.1.1.0
...0.0.0.1.1.0.1.1.0.0.0

Crossrefs

Sequence in context: A155293 A155311 A155289 * A155240 A155298 A155292

Adjacent sequences: A155303 A155304 A155305 * A155307 A155308 A155309

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved