A155435 Number of ways to place zero or more nonadjacent 2,1 2,2 3,0 3,1 3,3 4,2 4,3 5,2 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 4, 13, 28, 49, 105, 852, 6079, 29814, 128372, 780418, 9582912, 132900511, 1524452541, 17253579386, 257451880786, 5763064779401, 154341468962518

Offset

4,2

Links

Table of n, a(n) for n=4..21.

Example

Maximal 9 X 9 X 9 example
...........0
..........1.0
.........0.1.1
........1.1.0.1
.......0.0.1.1.0
......1.1.0.0.0.1
.....1.0.1.0.1.1.0
....0.1.1.0.1.0.1.1
...0.1.0.1.0.1.1.0.0

Crossrefs

Sequence in context: A272790 A273564 A155392 * A155371 A155355 A155356

Adjacent sequences: A155432 A155433 A155434 * A155436 A155437 A155438

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved