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A221427
Number of nX4 arrays of occupancy after each element moves to some horizontal or vertical neighbor, without consecutive moves in the same direction
1
1, 217, 4390, 194879, 6688747, 250167826, 9077677881, 333226472511, 12173165267828, 445650138090486, 16298689612917528, 596369615071847374, 21816211474871696352, 798162015570301300322, 29199761336459862799952
OFFSET
1,2
COMMENTS
Column 4 of A221429
LINKS
EXAMPLE
Some solutions for n=3
..1..1..1..0....1..1..1..1....0..1..0..0....1..1..1..0....1..1..0..1
..2..0..3..2....1..1..1..1....2..1..3..2....1..2..2..2....0..0..3..2
..1..0..1..0....1..2..1..0....2..0..1..0....0..2..0..0....2..1..1..0
CROSSREFS
Sequence in context: A320715 A183778 A250448 * A086026 A375816 A100794
KEYWORD
nonn
AUTHOR
R. H. Hardin Jan 15 2013
STATUS
approved