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A221226 Number of n X 2 arrays of occupancy after each element moves to some king-move neighbor, with no occupancy greater than 2. 2
1, 19, 137, 1033, 7877, 60223, 460713, 3524857, 26968225, 206327811, 1578551849, 12076946305, 92396113725, 706885768959, 5408092980713, 41375064828945, 316543208763529, 2421738125898019, 18527690050695513, 141747473284341977 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Column 2 of A221229.
LINKS
FORMULA
Empirical: a(n) = 15*a(n-1) - 71*a(n-2) + 123*a(n-3) - 78*a(n-4) + 14*a(n-5) - 12*a(n-6) + 8*a(n-7).
Empirical g.f.: x*(1 + 4*x - 77*x^2 + 204*x^3 - 150*x^4 + 28*x^5 + 8*x^6) / (1 - 15*x + 71*x^2 - 123*x^3 + 78*x^4 - 14*x^5 + 12*x^6 - 8*x^7). - Colin Barker, Mar 14 2018
EXAMPLE
Some solutions for n=3:
..0..2....1..2....1..1....2..1....2..2....1..2....0..1....1..1....0..0....1..0
..2..0....0..1....0..2....0..2....1..1....0..2....1..1....1..0....2..2....1..2
..1..1....1..1....1..1....0..1....0..0....1..0....1..2....2..1....0..2....0..2
CROSSREFS
Cf. A221229.
Sequence in context: A213122 A211092 A142746 * A139902 A140624 A244505
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 05 2013
STATUS
approved

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Last modified April 14 20:39 EDT 2024. Contains 371667 sequences. (Running on oeis4.)