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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A221225.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..22

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

Adjacent sequences:  A221220 A221221 A221222 * A221224 A221225 A221226

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 05 2013

STATUS

approved

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Last modified September 24 23:43 EDT 2022. Contains 356951 sequences. (Running on oeis4.)