A155276 Number of ways to place zero or more nonadjacent 0,0 1,0 2,0 2,1 3,2 4,3 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 7, 25, 55, 240, 1414, 11201, 99274, 1021345, 13018434, 219559590, 4642417867, 119857654154

Offset

4,2

Links

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

Example

Maximal 11 X 11 X 11 example
.............0
............1.0
...........0.1.0
..........1.0.1.0
.........1.0.1.1.1
........1.1.0.0.0.0
.......0.0.1.0.1.1.1
......0.1.0.1.0.0.1.0
.....0.1.0.0.0.1.0.1.0
....0.1.0.1.1.1.1.0.1.0
...1.1.1.0.0.0.0.1.0.0.0

Crossrefs

Sequence in context: A155240 A155298 A155292 * A155270 A155256 A155230

Adjacent sequences: A155273 A155274 A155275 * A155277 A155278 A155279

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved