A155428 Number of ways to place zero or more nonadjacent 1,1 2,0 2,1 3,2 4,3 5,4 5,5 6,4 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 4, 10, 19, 51, 170, 491, 1673, 7735, 36917, 181725, 1063340, 7115095, 51066154, 415590144, 3918376915

Offset

6,2

Links

Table of n, a(n) for n=6..21.

Example

Maximal 10 X 10 X 10 example
............0
...........0.1
..........1.1.0
.........0.0.1.0
........1.0.0.1.0
.......0.1.1.0.1.1
......0.1.0.0.1.0.0
.....0.1.0.1.0.0.0.1
....1.1.0.0.1.1.1.1.0
...0.0.1.0.1.0.0.0.1.0

Crossrefs

Sequence in context: A155269 A155322 A251176 * A155383 A155229 A155220

Adjacent sequences: A155425 A155426 A155427 * A155429 A155430 A155431

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved