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A221196 Number of n X 3 arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, with no occupancy greater than 2. 1
2, 10, 46, 212, 976, 4492, 20672, 95128, 437752, 2014400, 9269632, 42655888, 196288736, 903257824, 4156502752, 19126892096, 88015820416, 405020564416, 1863774679808, 8576493051520, 39466269101440, 181611106939904 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A221200.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..33

FORMULA

Empirical: a(n) = 6*a(n-1) - 6*a(n-2) - 2*a(n-3).

Empirical g.f.: 2*x*(1 - x - x^2) / (1 - 6*x + 6*x^2 + 2*x^3). - Colin Barker, Aug 04 2018

EXAMPLE

Some solutions for n=3:

..0..2..0....0..2..0....1..2..0....1..2..1....1..2..1....1..2..0....0..2..1

..1..2..2....0..2..2....0..2..1....1..2..0....0..2..1....1..2..0....0..2..2

..0..2..0....0..2..1....0..2..1....0..2..0....0..2..0....0..2..1....0..2..0

CROSSREFS

Cf. A221200.

Sequence in context: A290923 A106709 A204091 * A137193 A006213 A137635

Adjacent sequences:  A221193 A221194 A221195 * A221197 A221198 A221199

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 04 2013

STATUS

approved

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Last modified March 30 16:16 EDT 2020. Contains 333127 sequences. (Running on oeis4.)