A155358 Number of ways to place zero or more nonadjacent 1,0 1,1 2,1 2,2 3,1 3,2 4,2 4,3 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 7, 19, 37, 82, 439, 3622, 21277, 115970, 907157, 11150700, 162360713, 2286713291, 36892603949, 784002340205, 21639656177753

Offset

4,2

Links

Table of n, a(n) for n=4..19.

Example

Maximal 9 X 9 X 9 example
...........0
..........0.1
.........1.1.1
........1.1.1.0
.......0.1.0.0.0
......0.0.0.0.1.1
.....1.1.0.0.0.1.1
....1.1.1.1.0.1.1.0
...0.0.1.1.0.0.1.1.0

Crossrefs

Sequence in context: A155395 A155342 A155408 * A155353 A155317 A237052

Adjacent sequences: A155355 A155356 A155357 * A155359 A155360 A155361

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved