A155405 Number of ways to place zero or more nonadjacent 1,1 2,0 2,1 3,2 3,3 4,1 4,2 5,3 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 7, 19, 37, 61, 179, 1570, 9884, 43279, 162911, 1062503, 13577598, 173995382, 1740580398, 16367827293, 223104829665, 4754997792283, 115851743032210

Offset

5,2

Links

Table of n, a(n) for n=5..22.

Example

Maximal 10 X 10 X 10 example
............0
...........0.1
..........1.1.0
.........0.0.1.1
........0.1.1.0.0
.......0.0.0.1.0.0
......1.0.1.0.0.1.0
.....0.1.1.0.1.1.0.1
....1.1.0.1.0.0.1.1.0
...0.0.1.0.0.0.1.0.1.0

Crossrefs

Sequence in context: A002407 A098484 A155443 * A155448 A155446 A155372

Adjacent sequences: A155402 A155403 A155404 * A155406 A155407 A155408

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved