A155272 Number of ways to place zero or more nonadjacent 0,0 1,0 2,0 2,1 3,1 4,1 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 7, 19, 52, 260, 1220, 7357, 60311, 545790, 5982967, 83324072, 1383688085, 28070423509, 700749741616

Offset

4,2

Links

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

Example

Maximal 11 X 11 X 11 example
.............0
............0.1
...........0.0.1
..........1.0.1.1
.........1.0.0.1.0
........1.1.0.0.1.0
.......0.1.0.0.0.0.0
......0.1.0.0.1.1.1.0
.....0.0.0.1.1.1.0.0.0
....1.1.1.0.0.0.0.1.1.1
...0.0.1.1.1.0.1.1.1.0.0

Crossrefs

Sequence in context: A155246 A155414 A155374 * A092053 A072630 A002714

Adjacent sequences: A155269 A155270 A155271 * A155273 A155274 A155275

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved