A155315 Number of ways to place zero or more nonadjacent 1,0 2,0 2,1 2,2 3,0 3,1 4,2 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 7, 19, 37, 61, 503, 4407, 23093, 93285, 817543, 14192015, 204195517, 2243020429, 32774055967, 863753860919, 27738606644581, 798910205504069, 24797177099870103

Offset

4,2

Comments

Same series for 1,1 2,0 2,1 2,2 3,1 3,3 4,2 polyhexes.

Links

Table of n, a(n) for n=4..21.

Example

Maximal 9 X 9 X 9 example
...........0
..........1.0
.........1.1.1
........1.1.0.0
.......0.0.1.0.0
......0.0.0.0.0.1
.....1.1.1.0.1.1.1
....0.1.1.0.0.0.1.1
...0.1.0.1.0.0.1.0.0

Crossrefs

Sequence in context: A155406 A155352 A155361 * A155323 A121091 A213489

Adjacent sequences: A155312 A155313 A155314 * A155316 A155317 A155318

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved