A155217 Number of ways to place zero or more nonadjacent 1,0 1,1 2,1 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 2, 5, 10, 39, 205, 1026, 7765, 81639, 968094, 15354634, 328541791, 8661897260, 294910384475, 13193215967675, 751461392973699, 54989669970520419, 5219343962387133501, 636712452891464320519, 99887383227114543133737

Offset

1,2

Links

Table of n, a(n) for n=1..20.

Example

Maximal 13 X 13 X 13 example
...............1
..............1.1
.............0.0.0
............1.0.1.1
...........1.1.0.1.0
..........0.0.0.0.0.1
.........1.0.1.1.0.1.1
........1.1.0.1.0.0.0.0
.......0.0.0.0.0.1.1.0.1
......1.1.0.1.1.0.1.0.1.1
.....0.1.0.0.1.0.0.0.0.0.0
....1.0.0.1.0.0.1.0.1.1.0.1
...1.1.0.1.1.0.1.1.0.1.0.1.1

Crossrefs

Sequence in context: A018418 A363429 A290032 * A004143 A266162 A103036

Adjacent sequences: A155214 A155215 A155216 * A155218 A155219 A155220

Keyword

nonn

Author

R. H. Hardin Jan 22 2009

Status

approved