A155354 Number of ways to place zero or more nonadjacent 2,0 3,1 4,2 4,3 4,4 5,2 6,2 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 3, 7, 13, 21, 54, 165, 638, 2331, 9005, 38668, 204465, 1227713, 8257094, 59762784, 487017754, 4487006412, 47257428230, 557362552428

Offset

6,2

Links

Table of n, a(n) for n=6..24.

Example

Maximal 11 X 11 X 11 example
.............0
............0.0
...........0.0.1
..........0.0.1.0
.........1.1.1.0.0
........0.0.0.1.0.0
.......0.0.1.0.1.0.1
......0.0.1.0.0.0.1.0
.....1.1.1.0.1.1.1.0.0
....0.0.0.1.0.0.0.1.0.0
...0.0.0.0.1.0.0.0.1.0.0

Crossrefs

Sequence in context: A147335 A147464 A146058 * A136219 A078582 A051336

Adjacent sequences: A155351 A155352 A155353 * A155355 A155356 A155357

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved