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A221394 Number of n X 3 arrays of occupancy after each element stays put or moves to some horizontal, vertical or antidiagonal neighbor, with every occupancy equal to zero or two. 1
0, 18, 0, 631, 0, 23188, 0, 852298, 0, 31322020, 0, 1151041183, 0, 42298797564, 0, 1554405335830, 0, 57121595318958, 0, 2099115475346705, 0, 77138701114715724, 0, 2834707878337590102, 0, 104170392148337357776, 0, 3828073672066667898151, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 3 of A221396.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 48*a(n-2) - 440*a(n-4) + 998*a(n-6) - 873*a(n-8) + 252*a(n-10) + 16*a(n-12).

Empirical g.f.: x^2*(18 - 233*x^2 + 820*x^4 - 1050*x^6 + 412*x^8 + 46*x^10) / ((1 - x)*(1 + x)*(1 - 47*x^2 + 393*x^4 - 605*x^6 + 268*x^8 + 16*x^10)). - Colin Barker, Aug 05 2018

CROSSREFS

Cf. A221396.

Sequence in context: A096306 A231962 A052441 * A025602 A088126 A040327

Adjacent sequences:  A221391 A221392 A221393 * A221395 A221396 A221397

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 14 2013

STATUS

approved

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Last modified November 22 05:53 EST 2019. Contains 329388 sequences. (Running on oeis4.)