A155273 Number of ways to place zero or more nonadjacent 0,0 1,0 2,0 2,1 3,1 4,2 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 7, 19, 46, 163, 1024, 6441, 43301, 373095, 4261954, 57065692, 918668240, 18051831843, 438138199809

Offset

4,2

Links

Table of n, a(n) for n=4..17.

Example

Maximal 13 X 13 X 13 example
...............1
..............0.1
.............0.1.1
............1.0.1.0
...........1.0.1.0.1
..........1.1.0.0.0.1
.........0.1.0.0.0.1.1
........0.0.1.0.0.0.1.0
.......1.0.0.0.0.0.1.0.1
......1.0.0.1.1.1.0.0.0.1
.....1.1.0.1.1.0.0.1.0.1.1
....0.1.0.1.0.0.1.1.0.0.1.0
...0.0.1.0.0.1.1.1.0.0.1.0.0

Crossrefs

Sequence in context: A212955 A372881 A155415 * A277613 A278403 A143128

Adjacent sequences: A155270 A155271 A155272 * A155274 A155275 A155276

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved