A155322 Number of ways to place zero or more nonadjacent 0,0 1,0 1,1 2,1 3,1 3,2 4,2 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 4, 10, 19, 46, 199, 890, 4075, 20900, 140127, 1098924, 9985570, 103452546, 1269141243, 18318539114, 311054175156, 6154670827141

Offset

4,2

Links

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

Example

Maximal 9 X 9 X 9 example
...........0
..........0.0
.........0.1.1
........1.1.1.0
.......1.1.0.0.1
......0.0.0.0.1.1
.....1.1.0.0.0.1.0
....0.1.1.1.0.1.1.0
...0.0.0.1.1.0.1.0.0

Crossrefs

Sequence in context: A133952 A155348 A155269 * A251176 A155428 A155383

Adjacent sequences: A155319 A155320 A155321 * A155323 A155324 A155325

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved