A155371 Number of ways to place zero or more nonadjacent 1,1 2,0 2,1 3,1 3,2 3,3 4,1 4,3 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 4, 13, 28, 49, 110, 920, 6322, 30236, 123737, 790167, 10430919, 142197770, 1546938330, 16600218633, 257429254996, 6152180165653

Offset

4,2

Links

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

Example

Maximal 9 X 9 X 9 example
...........0
..........0.1
.........1.1.0
........0.1.1.1
.......0.1.0.1.0
......1.0.0.0.0.1
.....0.1.1.0.1.1.0
....1.1.1.0.0.1.1.1
...0.1.0.1.0.1.0.1.0

Crossrefs

Sequence in context: A273564 A155392 A155435 * A155355 A155356 A060488

Adjacent sequences: A155368 A155369 A155370 * A155372 A155373 A155374

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved