A155225 Number of ways to place zero or more nonadjacent 1,1 2,0 2,1 3,2 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 3, 7, 13, 38, 180, 805, 3814, 25700, 220335, 2064779, 23174247, 331474649, 5713874467, 116010028877, 2863484145009, 86429492811884, 3140385298427338, 137283404960168681, 7274093873738312075

Offset

3,2

Links

Table of n, a(n) for n=3..22.

Example

Maximal 10 X 10 X 10 example
............0
...........1.0
..........0.1.1
.........0.1.0.0
........1.0.0.1.0
.......0.1.1.0.1.1
......0.1.0.0.1.0.0
.....1.0.0.1.0.0.1.0
....0.1.1.0.1.1.0.1.1
...0.1.0.0.1.0.0.1.0.0

Crossrefs

Sequence in context: A147448 A146449 A145956 * A051842 A147447 A062605

Adjacent sequences: A155222 A155223 A155224 * A155226 A155227 A155228

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved