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A221246
Number of 2 X n arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor.
1
0, 9, 50, 484, 3864, 32400, 267264, 2214144, 18316800, 151585344, 1254325824, 10379534400, 85889605824, 710729930304, 5881230244800, 48666696727104, 402712880117184, 3332415765326400, 27575464553486784, 228184686537228864
OFFSET
1,2
COMMENTS
Row 2 of A221245.
LINKS
FORMULA
Empirical: a(n) = 9*a(n-1) - 54*a(n-3) + 36*a(n-4) for n>5.
Empirical g.f.: x^2*(9 - 31*x + 34*x^2 - 6*x^3) / ((1 - 9*x + 6*x^2)*(1 - 6*x^2)). - Colin Barker, Aug 04 2018
EXAMPLE
Some solutions for n=3:
1 3 1 0 3 0 2 2 0 0 4 2 0 2 0 1 4 1 0 2 2
0 1 0 0 1 2 0 2 0 0 0 0 1 2 1 0 0 0 0 2 0
CROSSREFS
Cf. A221245.
Sequence in context: A188210 A308646 A338510 * A002462 A210061 A034814
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 06 2013
STATUS
approved