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A221323 Number of n X 3 arrays of occupancy after each element stays put or moves to some horizontal or antidiagonal neighbor, with no occupancy greater than 2. 1
7, 119, 2008, 33873, 571358, 9637322, 162555929, 2741882383, 46248186229, 780082534460, 13157894317753, 221938287447408, 3743501973486176, 63142809559541159, 1065049364666447387, 17964518161956501475 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Column 3 of A221328.
LINKS
FORMULA
Empirical: a(n) = 23*a(n-1) - 110*a(n-2) + 111*a(n-3) - 6*a(n-4) - 8*a(n-5).
Empirical g.f.: x*(1 - x)*(7 - 35*x + 6*x^2 + 8*x^3) / (1 - 23*x + 110*x^2 - 111*x^3 + 6*x^4 + 8*x^5). - Colin Barker, Aug 05 2018
EXAMPLE
Some solutions for n=3:
..2..1..0....2..2..0....1..1..0....1..1..1....2..1..0....1..0..1....1..0..2
..2..0..1....0..2..0....2..0..2....0..2..1....1..0..1....1..2..0....2..1..0
..1..0..2....0..1..2....0..2..1....1..0..2....2..2..0....1..2..1....0..2..1
CROSSREFS
Cf. A221328.
Sequence in context: A076283 A057769 A221031 * A268300 A304917 A113667
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 11 2013
STATUS
approved

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Last modified February 28 22:27 EST 2024. Contains 370400 sequences. (Running on oeis4.)