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A221223
Number of n X 2 arrays of occupancy after each element stays put or moves to some king-move neighbor.
1
3, 35, 400, 4525, 51025, 574800, 6473175, 72891475, 820773600, 9242002325, 104065684825, 1171786908400, 13194399201775, 148569807813675, 1672905820612800, 18837029565221725, 212106191270112225
OFFSET
1,1
COMMENTS
Column 2 of A221225.
LINKS
FORMULA
Empirical: a(n) = 15*a(n-1) - 43*a(n-2) + 10*a(n-3).
Empirical g.f.: x*(3 - 10*x + 4*x^2) / (1 - 15*x + 43*x^2 - 10*x^3). - Colin Barker, Aug 04 2018
EXAMPLE
Some solutions for n=3:
..0..0....2..0....2..1....2..0....1..3....0..0....3..1....0..0....2..1....2..0
..4..0....2..1....0..0....2..0....0..0....1..2....1..1....5..1....0..1....0..2
..0..2....1..0....1..2....1..1....0..2....3..0....0..0....0..0....2..0....2..0
CROSSREFS
Cf. A221225.
Sequence in context: A086043 A221774 A221687 * A006767 A065929 A161495
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 05 2013
STATUS
approved