A155271 Number of ways to place zero or more nonadjacent 0,0 1,0 2,0 2,1 3,0 4,0 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 7, 25, 105, 639, 3603, 22857, 241966, 2928219, 43585143, 850752020, 19021431704, 530984535190

Offset

4,2

Links

Table of n, a(n) for n=4..16.

Example

Maximal 11 X 11 X 11 example
.............1
............1.0
...........1.1.0
..........1.0.0.0
.........1.0.1.0.0
........0.0.0.1.1.0
.......1.0.0.0.1.0.1
......1.0.0.0.0.1.0.1
.....1.0.0.0.0.0.1.0.1
....1.1.0.0.0.1.0.0.1.1
...1.0.0.1.1.1.1.1.0.0.1

Crossrefs

Sequence in context: A141627 A289606 A102900 * A200152 A255280 A327627

Adjacent sequences: A155268 A155269 A155270 * A155272 A155273 A155274

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved