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A155322 Number of ways to place zero or more nonadjacent 0,0 1,0 1,1 2,1 3,1 3,2 4,2 polyhexes in any orientation on a planar nXnXn triangular grid. 0
1, 4, 10, 19, 46, 199, 890, 4075, 20900, 140127, 1098924, 9985570, 103452546, 1269141243, 18318539114, 311054175156, 6154670827141 (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

..........0.0

.........0.1.1

........1.1.1.0

.......1.1.0.0.1

......0.0.0.0.1.1

.....1.1.0.0.0.1.0

....0.1.1.1.0.1.1.0

...0.0.0.1.1.0.1.0.0

CROSSREFS

Sequence in context: A133952 A155348 A155269 * A251176 A155428 A155383

Adjacent sequences:  A155319 A155320 A155321 * A155323 A155324 A155325

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 22 2009

STATUS

approved

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Last modified January 17 09:32 EST 2020. Contains 330949 sequences. (Running on oeis4.)