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A155323 Number of ways to place zero or more nonadjacent 0,0 1,0 2,0 2,1 2,2 3,1 4,2 polyhexes in any orientation on a planar nXnXn triangular grid. 0
1, 7, 19, 37, 61, 547, 3879, 20553, 82301, 862099, 11383399, 147116137, 1584915709, 26192809787, 600459150255, 15941874201057 (list; graph; refs; listen; history; text; internal format)
OFFSET

4,2

COMMENTS

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

LINKS

Table of n, a(n) for n=4..19.

EXAMPLE

Maximal 9 X 9 X 9 example

...........1

..........0.1

.........1.1.1

........0.0.1.0

.......0.0.1.0.0

......0.0.0.0.0.0

.....1.0.1.0.1.1.1

....0.1.1.0.1.1.0.0

...1.1.1.0.1.0.1.0.0

CROSSREFS

Sequence in context: A155352 A155361 A155315 * A121091 A213489 A155394

Adjacent sequences:  A155320 A155321 A155322 * A155324 A155325 A155326

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 22 2009

STATUS

approved

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Last modified September 1 10:25 EDT 2014. Contains 246292 sequences.