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A221933
Number of n X 3 arrays of occupancy after each element stays put or moves to some horizontal or antidiagonal neighbor, without move-in move-out straight through or left turns.
1
6, 105, 1599, 24535, 376389, 5773962, 88575493, 1358791848, 20844539836, 319765562424, 4905362062396, 75250682972713, 1154382737872290, 17708802802243865, 271661803663808763, 4167426584055854255
OFFSET
1,1
COMMENTS
Column 3 of A221937.
LINKS
FORMULA
Empirical: a(n) = 14*a(n-1) + 21*a(n-2) - 5*a(n-3) - 26*a(n-4) + a(n-5).
Empirical g.f.: x*(6 + 21*x + 3*x^2 - 26*x^3 + x^4) / (1 - 14*x - 21*x^2 + 5*x^3 + 26*x^4 - x^5). - Colin Barker, Aug 11 2018
EXAMPLE
Some solutions for n=3:
..0..3..1....1..3..0....2..0..1....1..0..1....2..0..1....1..2..0....0..2..1
..0..1..0....0..2..0....1..0..1....2..1..0....2..0..0....0..3..0....0..4..0
..0..3..1....1..2..0....2..2..0....1..3..0....1..2..1....1..0..2....1..0..1
CROSSREFS
Cf. A221937.
Sequence in context: A077289 A279520 A309378 * A110342 A227207 A126467
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 01 2013
STATUS
approved