A155255 Number of ways to place zero or more nonadjacent 1,1 2,1 2,2 3,0 3,1 4,1 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 7, 19, 37, 138, 709, 5288, 35178, 273388, 2852364, 38034180, 614782409, 11580813304, 263078868069, 7443277204441, 259134680265818

Offset

4,2

Links

Table of n, a(n) for n=4..19.

Example

Maximal 11 X 11 X 11 example
.............0
............0.1
...........0.1.1
..........1.1.0.0
.........0.1.0.1.0
........0.0.0.1.1.0
.......0.0.0.0.0.1.1
......1.1.0.1.1.0.1.0
.....0.1.0.0.1.0.0.0.1
....0.1.0.0.1.0.1.1.1.1
...0.1.1.0.1.1.0.1.0.0.0

Crossrefs

Sequence in context: A155442 A155324 A155325 * A155251 A155239 A217421

Adjacent sequences: A155252 A155253 A155254 * A155256 A155257 A155258

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved