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A221134
Number of nX3 arrays of occupancy after each element moves to some horizontal or vertical neighbor, with no occupancy greater than 2
1
2, 49, 656, 12544, 200072, 3485689, 58132316, 990486784, 16699002692, 282999528529, 4783766470826, 80965479678724, 1369496232351362, 23171487659654569, 391996208325992186, 6631958618350959364
OFFSET
1,1
COMMENTS
Column 3 of A221139
LINKS
FORMULA
Empirical: a(n) = 21*a(n-1) -1450*a(n-3) +4782*a(n-4) -372*a(n-5) +1450*a(n-6) +69*a(n-8) +a(n-9)
EXAMPLE
Some solutions for n=3
..2..1..1....1..2..0....0..2..2....2..1..0....0..2..2....0..1..2....0..2..2
..1..0..1....1..2..0....1..1..1....2..1..2....0..2..1....2..0..1....1..0..1
..0..2..1....1..2..0....0..1..1....0..0..1....0..2..0....2..1..0....2..1..0
CROSSREFS
Sequence in context: A028479 A189389 A001568 * A243720 A369943 A210922
KEYWORD
nonn
AUTHOR
R. H. Hardin Jan 02 2013
STATUS
approved