A155310 Number of ways to place zero or more nonadjacent 1,1 2,0 2,1 3,2 4,3 4,4 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 7, 25, 55, 184, 1073, 8931, 73812, 639377, 7143496, 110082014, 2154472585, 48658986855, 1307630014597

Offset

4,2

Links

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

Example

Maximal 12 X 12 X 12 example
..............0
.............1.0
............0.1.1
...........0.1.0.0
..........1.1.0.0.1
.........0.0.0.1.1.0
........0.0.1.0.0.1.0
.......1.1.1.0.1.0.1.1
......1.0.0.1.0.1.0.0.0
.....0.0.1.0.0.1.0.1.0.0
....1.1.1.0.1.1.0.0.1.1.1
...1.0.0.1.0.0.1.0.1.0.0.1

Crossrefs

Sequence in context: A155250 A155260 A155244 * A155288 A155293 A155311

Adjacent sequences: A155307 A155308 A155309 * A155311 A155312 A155313

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved