A155220 Number of ways to place zero or more nonadjacent 1,0 1,1 2,1 2,2 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 4, 10, 19, 109, 692, 3521, 31519, 398368, 5171923, 89984622, 2185316954, 63742209751, 2336382318172, 113584162550499, 6998045379053544, 543364715394976386, 54434393498867053000, 6983398903852168886345

Offset

2,2

Links

Table of n, a(n) for n=2..20.

Example

Maximal 9 X 9 X 9 example
...........0
..........1.1
.........1.1.0
........0.0.0.0
.......1.1.0.1.1
......1.1.0.0.1.1
.....0.0.0.0.0.0.0
....1.1.0.1.1.0.1.1
...1.1.0.0.1.1.0.1.1

Crossrefs

Sequence in context: A155428 A155383 A155229 * A300018 A268221 A086176

Adjacent sequences: A155217 A155218 A155219 * A155221 A155222 A155223

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved