A155286 Number of ways to place zero or more nonadjacent 1,1 2,1 3,0 3,1 4,2 4,3 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 7, 25, 55, 97, 706, 9275, 70904, 406991, 3864451, 77404600, 1807280192, 33936037037, 736180071815, 24815800630395

Offset

4,2

Links

Table of n, a(n) for n=4..18.

Example

Maximal 11 X 11 X 11 example
.............0
............0.1
...........1.1.0
..........1.0.1.0
.........0.0.0.1.0
........0.0.0.0.0.0
.......0.0.0.0.1.0.0
......1.0.1.1.1.0.1.0
.....1.0.0.0.0.1.0.1.0
....0.1.1.1.0.1.0.0.1.1
...0.1.0.0.0.0.0.1.1.0.0

Crossrefs

Sequence in context: A304075 A357196 A227776 * A155313 A213390 A071778

Adjacent sequences: A155283 A155284 A155285 * A155287 A155288 A155289

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved