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A221404 Number of nX3 arrays of occupancy after each element stays put or moves to some horizontal or vertical neighbor, with every occupancy equal to zero or two 1
0, 16, 0, 436, 0, 12668, 0, 368268, 0, 10705360, 0, 311197280, 0, 9046269888, 0, 262968117056, 0, 7644280337936, 0, 222213327464336, 0, 6459569820912704, 0, 187774705858714240, 0, 5458465675503960896, 0, 158673381440822516672, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 3 of A221408

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 36*a(n-2) -200*a(n-4) -40*a(n-6) -84*a(n-8) +80*a(n-10) -20*a(n-12) +80*a(n-14)

EXAMPLE

Some solutions for n=4

..0..2..0....2..0..2....2..0..2....0..2..0....0..2..0....2..0..0....0..2..2

..2..0..0....2..0..0....0..0..2....0..0..2....0..2..0....0..2..2....0..0..0

..2..2..2....0..0..2....0..0..2....2..2..2....2..0..2....0..0..0....2..0..2

..0..2..0....2..2..0....2..0..2....0..0..2....2..0..2....2..2..2....2..2..0

CROSSREFS

Sequence in context: A123935 A169764 A002607 * A221726 A221729 A219950

Adjacent sequences:  A221401 A221402 A221403 * A221405 A221406 A221407

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 15 2013

STATUS

approved

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Last modified June 19 00:04 EDT 2021. Contains 345125 sequences. (Running on oeis4.)