A155238 Number of ways to place zero or more nonadjacent 1,0 1,1 2,0 3,0 4,1 polyhexes in any orientation on a planar n X n X n triangular grid.

1, 4, 13, 28, 125, 568, 3422, 27373, 226848, 2490002, 34395449, 564841115, 11835714950, 297683710781, 9228089921657

Offset

3,2

Links

Table of n, a(n) for n=3..17.

Example

Maximal 9 X 9 X 9 example
...........0
..........0.0
.........1.1.1
........1.0.0.1
.......0.0.0.0.0
......1.1.0.0.1.1
.....1.0.0.0.0.0.1
....1.0.1.0.0.1.0.1
...0.1.0.1.1.1.0.1.0

Crossrefs

Sequence in context: A155326 A155257 A155224 * A155320 A155279 A155331

Adjacent sequences: A155235 A155236 A155237 * A155239 A155240 A155241

Keyword

nonn

Author

R. H. Hardin, Jan 22 2009

Status

approved