A155217 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give

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

(list; graph; refs; listen; history; text; internal format)

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