A155305 Number of ways to place zero or more nonadjacent 1,1 2,0 2,1 3,2 3,3 4,4 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 7, 25, 64, 217, 1298, 10738, 90390, 827265, 9950319, 159818687, 3209355205, 75527888278, 2156343784054

Offset

4,2

Links

Table of n, a(n) for n=4..17.

Example

Maximal 11 X 11 X 11 example
.............1
............0.1
...........0.1.0
..........0.0.1.1
.........0.0.1.0.0
........1.0.0.0.0.1
.......0.1.1.0.1.1.0
......1.1.0.0.0.0.1.1
.....1.0.0.1.0.1.0.0.1
....0.0.1.1.0.0.1.1.0.0
...0.1.1.0.1.0.1.0.1.1.0

Crossrefs

Sequence in context: A299273 A001845 A127765 * A155290 A056685 A299262

Adjacent sequences: A155302 A155303 A155304 * A155306 A155307 A155308

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved