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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
OFFSET
1,2
COMMENTS
Column 3 of A221408
LINKS
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
KEYWORD
nonn
AUTHOR
R. H. Hardin Jan 15 2013
STATUS
approved