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A155371 Number of ways to place zero or more nonadjacent 1,1 2,0 2,1 3,1 3,2 3,3 4,1 4,3 polyhexes in any orientation on a planar nXnXn triangular grid. 0
1, 4, 13, 28, 49, 110, 920, 6322, 30236, 123737, 790167, 10430919, 142197770, 1546938330, 16600218633, 257429254996, 6152180165653 (list; graph; refs; listen; history; text; internal format)
OFFSET

4,2

LINKS

Table of n, a(n) for n=4..20.

EXAMPLE

Maximal 9 X 9 X 9 example

...........0

..........0.1

.........1.1.0

........0.1.1.1

.......0.1.0.1.0

......1.0.0.0.0.1

.....0.1.1.0.1.1.0

....1.1.1.0.0.1.1.1

...0.1.0.1.0.1.0.1.0

CROSSREFS

Sequence in context: A273564 A155392 A155435 * A155355 A155356 A060488

Adjacent sequences:  A155368 A155369 A155370 * A155372 A155373 A155374

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 22 2009

STATUS

approved

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Last modified October 20 03:04 EDT 2021. Contains 348099 sequences. (Running on oeis4.)