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A229504 Number of defective 3-colorings of an n X 2 0..2 array connected diagonally and antidiagonally with exactly one mistake, and colors introduced in row-major 0..2 order. 1
0, 6, 48, 288, 1536, 7680, 36864, 172032, 786432, 3538944, 15728640, 69206016, 301989888, 1308622848, 5637144576, 24159191040, 103079215104, 438086664192, 1855425871872, 7834020347904, 32985348833280, 138538465099776 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 2 of A229510.

LINKS

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

FORMULA

Empirical: a(n) = 8*a(n-1) -16*a(n-2).

a(n) = 3/2*(n-1)*4^(n-1) for n = 1..210. - Jérôme Germoni, Sep 18 2015

Empirical g.f.: 6*x^2 / (1 - 4*x)^2. - Colin Barker, Jun 16 2017

EXAMPLE

Some solutions for n=4:

..0..1....0..0....0..1....0..1....0..0....0..1....0..1....0..1....0..1....0..1

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

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

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

CROSSREFS

Sequence in context: A056284 A293967 A246587 * A100740 A043020 A073994

Adjacent sequences:  A229501 A229502 A229503 * A229505 A229506 A229507

KEYWORD

nonn

AUTHOR

R. H. Hardin, Sep 25 2013

STATUS

approved

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Last modified September 22 03:54 EDT 2020. Contains 337289 sequences. (Running on oeis4.)