A155251 Number of ways to place zero or more nonadjacent 1,0 1,1 2,1 2,2 3,1 4,1 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 7, 19, 37, 138, 709, 5384, 34764, 263230, 2819561, 38049276, 603759584, 11166092240, 253333757097, 7225054921993

Offset

4,2

Links

Table of n, a(n) for n=4..18.

Example

Maximal 12 X 12 X 12 example
..............0
.............1.1
............1.1.0
...........0.0.1.0
..........0.0.0.1.0
.........1.1.0.0.0.1
........1.1.0.1.1.1.1
.......0.0.1.0.0.0.1.0
......0.1.0.1.0.1.0.0.0
.....0.1.0.0.0.1.0.0.0.1
....1.1.0.0.1.1.0.1.1.1.1
...0.1.1.0.0.1.1.0.0.0.1.0

Crossrefs

Sequence in context: A155324 A155325 A155255 * A155239 A217421 A155376

Adjacent sequences: A155248 A155249 A155250 * A155252 A155253 A155254

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved