

A221223


Number of n X 2 arrays of occupancy after each element stays put or moves to some kingmove neighbor.


1



3, 35, 400, 4525, 51025, 574800, 6473175, 72891475, 820773600, 9242002325, 104065684825, 1171786908400, 13194399201775, 148569807813675, 1672905820612800, 18837029565221725, 212106191270112225
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OFFSET

1,1


COMMENTS



LINKS



FORMULA

Empirical: a(n) = 15*a(n1)  43*a(n2) + 10*a(n3).
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



KEYWORD

nonn


AUTHOR



STATUS

approved



