A155443 Number of ways to place zero or more nonadjacent 2,1 3,0 3,1 4,2 4,3 4,4 5,2 6,2 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 7, 19, 37, 61, 156, 946, 6587, 32063, 128930, 679319, 5663620, 64380331, 713842124, 7200710477, 81450733059, 1198927050536

Offset

6,2

Links

Table of n, a(n) for n=6..22.

Example

Maximal 11 X 11 X 11 example
.............0
............0.0
...........0.1.0
..........0.0.1.1
.........1.1.1.0.0
........0.0.0.1.0.0
.......0.0.1.0.1.0.1
......1.0.1.0.0.0.1.0
.....0.1.1.0.1.1.1.0.0
....0.1.0.1.0.0.0.1.1.0
...0.0.0.0.1.0.0.1.0.0.0

Crossrefs

Sequence in context: A133323 A002407 A098484 * A155405 A155448 A155446

Adjacent sequences: A155440 A155441 A155442 * A155444 A155445 A155446

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved