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A217632 Number of nX3 arrays of the minimum value of corresponding elements and their horizontal and vertical neighbors in a random 0..1 nX3 array 6
0, 4, 16, 66, 244, 968, 3726, 14520, 56352, 218978, 850620, 3304624, 12837742, 49872976, 193747784, 752680930, 2924043092, 11359448344, 44129645550, 171436683864, 666004286592, 2587320999714, 10051331417116, 39047827550656 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Also, number of maximal independent sets in the 3-dimensional (2, 3, n) grid graph. [Euler et al.] - N. J. A. Sloane, Nov 21 2013

Column 3 of A217637.

LINKS

R. H. Hardin, Table of n, a(n) for n = 0..184

R. Euler, P. Oleksik, Z. Skupien, Counting Maximal Distance-Independent Sets in Grid Graphs, Discussiones Mathematicae Graph Theory. Volume 33, Issue 3, Pages 531-557, ISSN (Print) 2083-5892, July 2013; http://www.degruyter.com/view/j/dmgt.2013.33.issue-3/dmgt.1707/dmgt.1707.xml

FORMULA

Empirical: a(n) = 2*a(n-1) +9*a(n-2) -2*a(n-3) -17*a(n-4) -4*a(n-5) +8*a(n-6) -3*a(n-7) +a(n-8) -3*a(n-9) -2*a(n-10) +4*a(n-11)

Euler et al. give an explicit g.f. and recurrence, and so (presumably) prove this recurrence is correct. - N. J. A. Sloane, Nov 21 2013

EXAMPLE

Some solutions for n=3

..1..0..0....0..0..0....0..0..0....1..0..0....0..0..1....0..0..1....1..1..0

..0..1..0....0..0..0....0..0..1....0..0..0....0..0..1....0..0..1....1..0..0

..0..0..1....0..1..1....0..0..1....1..0..1....0..0..0....0..0..1....0..0..0

CROSSREFS

Cf. A217637.

Sequence in context: A099781 A026872 A081915 * A026762 A277871 A082307

Adjacent sequences:  A217629 A217630 A217631 * A217633 A217634 A217635

KEYWORD

nonn

AUTHOR

R. H. Hardin Oct 09 2012

STATUS

approved

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Last modified March 25 21:57 EDT 2019. Contains 321477 sequences. (Running on oeis4.)