A155219 Number of ways to place zero or more nonadjacent 0,0 1,0 2,0 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 4, 10, 45, 176, 1305, 10079, 117352, 1561149, 29980210, 704867467, 22571926686, 912535595499, 49246939684046, 3416075823339525, 312263317852780140

Offset

2,2

Links

Table of n, a(n) for n=2..17.

Example

Maximal 13 X 13 X 13 example
...............1
..............1.0
.............1.0.1
............0.0.0.1
...........1.1.1.0.1
..........0.0.0.0.0.0
.........1.0.1.1.1.0.1
........1.0.0.0.0.0.1.0
.......1.0.1.1.1.0.1.0.1
......0.0.0.0.0.0.0.0.0.1
.....1.0.1.1.1.0.1.1.1.0.1
....1.0.0.0.0.0.0.0.0.0.0.0
...1.0.1.1.1.0.1.1.1.0.1.1.1

Crossrefs

Sequence in context: A155278 A155237 A155223 * A153985 A184481 A149227

Adjacent sequences: A155216 A155217 A155218 * A155220 A155221 A155222

Keyword

nonn,more,hard

Author

R. H. Hardin Jan 22 2009

Status

approved