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A155260 Number of ways to place zero or more nonadjacent 1,0 1,1 2,1 2,2 3,1 4,2 polyhexes in any orientation on a planar nXnXn triangular grid. 0
1, 7, 25, 55, 130, 1405, 16466, 116148, 894657, 15191483, 400416491, 9046002744, 215811308360, 8089887873673, 451390921829837 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,2

COMMENTS

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

LINKS

Table of n, a(n) for n=3..17.

EXAMPLE

Maximal 11 X 11 X 11 example

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

............1.1

...........0.1.1

..........1.1.0.0

.........0.0.0.1.1

........1.0.1.0.1.1

.......1.1.1.0.1.0.0

......0.1.0.0.0.1.0.1

.....1.0.0.1.1.0.0.1.0

....1.1.1.0.0.1.1.0.1.1

...0.1.0.1.0.1.1.0.1.1.0

CROSSREFS

Sequence in context: A213390 A071778 A155250 * A155244 A155310 A155288

Adjacent sequences:  A155257 A155258 A155259 * A155261 A155262 A155263

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 22 2009

STATUS

approved

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Last modified December 16 04:05 EST 2019. Contains 330013 sequences. (Running on oeis4.)