A155355 Number of ways to place zero or more nonadjacent 1,1 2,1 2,2 3,0 3,1 3,2 3,3 4,1 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 4, 13, 28, 49, 171, 1310, 8460, 42491, 242978, 2107793, 27648766, 373047925, 4984501036, 77677934468, 1580716536075, 41780194476260

Offset

4,2

Comments

Same series for 1,1 2,1 3,0 3,1 3,2 3,3 4,1 polyhexes.

Links

Table of n, a(n) for n=4..20.

Example

Maximal 9 X 9 X 9 example
...........0
..........1.0
.........1.1.0
........1.1.1.1
.......0.0.0.1.0
......1.1.0.0.0.1
.....0.1.0.0.0.1.1
....0.1.1.0.1.1.1.1
...0.1.1.1.0.1.0.0.0

Crossrefs

Sequence in context: A155392 A155435 A155371 * A155356 A060488 A054968

Adjacent sequences: A155352 A155353 A155354 * A155356 A155357 A155358

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved