A155420 Number of ways to place zero or more nonadjacent 1,1 2,0 2,1 3,2 4,2 5,3 5,4 6,3 polyhexes in any orientation on a planar n X n X n triangular grid.

1, 7, 19, 37, 67, 234, 1126, 6422, 32270, 161586, 990365, 7766402, 74447984, 789199485, 8923308481

Offset

6,2

Links

Table of n, a(n) for n=6..20.

Example

Maximal 11 X 11 X 11 example
.............0
............0.0
...........0.1.0
..........0.0.1.1
.........0.1.1.0.0
........1.1.0.0.0.1
.......0.0.1.0.1.1.0
......1.0.0.0.0.0.1.0
.....0.1.1.0.1.0.1.0.0
....0.1.0.1.1.0.0.1.1.0
...0.0.0.0.0.1.0.1.0.0.0

Crossrefs

Sequence in context: A288021 A155394 A155412 * A155434 A155378 A155438

Adjacent sequences: A155417 A155418 A155419 * A155421 A155422 A155423

Keyword

nonn

Author

R. H. Hardin, Jan 22 2009

Status

approved