A155312 Number of ways to place zero or more nonadjacent 0,0 1,0 2,1 3,2 4,3 5,3 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 7, 19, 43, 172, 775, 4404, 27025, 209013, 1889445, 19997883, 257549066, 3935142613

Offset

5,2

Links

Table of n, a(n) for n=5..17.

Example

Maximal 13 X 13 X 13 example
...............0
..............0.0
.............1.1.0
............0.0.1.0
...........0.0.0.1.0
..........0.1.1.0.1.1
.........0.1.0.0.0.0.0
........0.1.0.1.0.1.0.1
.......1.1.0.1.0.1.0.1.0
......0.0.0.0.1.0.1.0.1.0
.....0.0.0.1.0.1.0.1.0.1.0
....1.1.1.1.0.0.1.0.1.0.1.0
...1.0.0.0.0.0.1.0.1.0.1.0.0

Crossrefs

Sequence in context: A155427 A155403 A155350 * A155351 A155430 A155247

Adjacent sequences: A155309 A155310 A155311 * A155313 A155314 A155315

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved