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A229695 Number of defective 3-colorings of a 2Xn 0..2 array connected horizontally and antidiagonally with exactly two mistakes, and colors introduced in row-major 0..2 order 1
0, 3, 43, 245, 1171, 5077, 20691, 80757, 305235, 1125333, 4067091, 14461173, 50723091, 175867605, 603736659, 2054728053, 6940088019, 23284024533, 77651501715, 257577229557, 850273182099, 2794463987157, 9147385165779 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Row 2 of A229694

LINKS

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

FORMULA

Empirical: a(n) = 9*a(n-1) -27*a(n-2) +27*a(n-3) for n>6.

Empirical: G.f. 3*x^2+43*x^3  -x^4*(245-1034*x+1153*x^2) / (3*x-1)^3. - R. J. Mathar, Sep 29 2013

EXAMPLE

Some solutions for n=3

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

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

CROSSREFS

Sequence in context: A030990 A306970 A054698 * A060559 A197778 A321970

Adjacent sequences:  A229692 A229693 A229694 * A229696 A229697 A229698

KEYWORD

nonn

AUTHOR

R. H. Hardin, Sep 27 2013

STATUS

approved

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Last modified December 12 17:59 EST 2019. Contains 329960 sequences. (Running on oeis4.)