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A155391 Number of ways to place zero or more nonadjacent 1,1 2,1 3,1 4,0 4,1 5,2 6,3 7,4 polyhexes in any orientation on a planar nXnXn triangular grid. 0
1, 7, 19, 37, 106, 313, 1348, 6817, 32547, 189413, 1214982, 8891593, 78525607, 761546216 (list; graph; refs; listen; history; text; internal format)
OFFSET

7,2

LINKS

Table of n, a(n) for n=7..20.

EXAMPLE

Maximal 11 X 11 X 11 example

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

............0.0

...........0.0.0

..........0.0.0.0

.........0.1.0.1.0

........0.1.0.0.1.0

.......0.1.0.0.0.1.0

......1.1.0.0.0.0.1.1

.....0.0.1.0.0.0.1.0.0

....0.0.0.1.0.0.1.0.0.0

...0.0.0.0.1.0.1.0.0.0.0

CROSSREFS

Sequence in context: A155243 A155417 A155416 * A155400 A155359 A098481

Adjacent sequences:  A155388 A155389 A155390 * A155392 A155393 A155394

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 22 2009

STATUS

approved

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Last modified November 14 07:07 EST 2019. Contains 329110 sequences. (Running on oeis4.)