A155221 Number of ways to place zero or more nonadjacent 1,1 2,0 2,1 2,2 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 7, 25, 70, 500, 7410, 81126, 1254921, 35099024, 1318005942, 58686994598, 3824088664649, 368413623404582, 47231934784100638, 8189977602765893624

Offset

2,2

Links

Table of n, a(n) for n=2..16.

Example

Maximal 9 X 9 X 9 example
...........1
..........1.1
.........0.0.1
........1.0.0.0
.......1.1.0.0.1
......1.0.0.1.1.1
.....0.0.1.0.0.0.0
....1.0.0.1.1.0.1.0
...1.1.1.0.1.0.1.1.1

Crossrefs

Sequence in context: A240156 A155245 A155291 * A213569 A299269 A048477

Adjacent sequences: A155218 A155219 A155220 * A155222 A155223 A155224

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved