A155258 - OEIS

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A155258

Number of ways to place zero or more nonadjacent 0,0 1,0 1,1 2,0 3,0 4,0 polyhexes in any orientation on a planar nXnXn triangular grid.

1, 7, 25, 90, 688, 4109, 25041, 287360, 3402527, 48602011, 1011814868, 22922047752

(list; graph; refs; listen; history; text; internal format)

OFFSET

4,2

LINKS

Table of n, a(n) for n=4..15.

EXAMPLE

Maximal 13 X 13 X 13 example

...............1

..............1.0

.............1.0.1

............1.0.1.1

...........1.1.0.0.1

..........0.0.0.0.0.1

.........1.0.1.1.0.0.1

........1.0.0.1.0.1.0.0

.......1.0.1.0.1.0.1.0.1

......1.0.1.1.0.1.0.1.0.1

.....1.1.0.0.1.0.1.0.1.0.1

....0.0.0.1.0.1.0.0.1.1.0.1

...1.1.1.1.1.0.1.0.0.0.0.1.1

CROSSREFS

Sequence in context: A279216 A245769 A146933 * A261722 A256370 A199116

Adjacent sequences: A155255 A155256 A155257 * A155259 A155260 A155261

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 22 2009

STATUS

approved