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A155274 Number of ways to place zero or more nonadjacent 1,1 2,1 3,0 3,1 3,2 4,3 polyhexes in any orientation on a planar nXnXn triangular grid. 0
1, 3, 9, 19, 33, 122, 733, 3984, 18507, 108272, 955732, 10449887, 117050472, 1441595909, 22302751858, 436682293027, 10013251106293, 259927601261214 (list; graph; refs; listen; history; text; internal format)
OFFSET

4,2

LINKS

Table of n, a(n) for n=4..21.

EXAMPLE

Maximal 13 X 13 X 13 example

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

..............0.1

.............0.1.0

............1.1.1.0

...........0.0.0.1.0

..........0.1.0.0.0.1

.........0.1.0.0.0.1.0

........1.1.1.0.1.1.1.0

.......0.0.0.1.0.0.0.1.0

......1.0.0.0.0.0.1.0.0.1

.....0.1.0.0.1.1.1.0.0.1.0

....0.1.1.1.0.0.1.0.1.1.1.0

...0.1.0.0.0.0.0.1.0.0.0.1.0

CROSSREFS

Sequence in context: A146465 A147119 A146184 * A058058 A062748 A325666

Adjacent sequences:  A155271 A155272 A155273 * A155275 A155276 A155277

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 22 2009

STATUS

approved

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Last modified May 31 20:23 EDT 2020. Contains 334748 sequences. (Running on oeis4.)