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A229474 Number of defective 4-colorings of an n X 3 0..3 array connected horizontally, antidiagonally and vertically with exactly one mistake, and colors introduced in row-major 0..3 order. 1
2, 42, 420, 3328, 23964, 163528, 1077588, 6927888, 43728652, 272112472, 1674170052, 10205294240, 61731029116, 370982129640, 2217078993972, 13186003918640, 78093132909036, 460783597042808, 2709856102785444 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 14*a(n-1) - 65*a(n-2) + 112*a(n-3) - 64*a(n-4) for n>5.

Empirical g.f.: 2*x*(1 + 7*x - 19*x^2 - 23*x^3 + 48*x^4) / (1 - 7*x + 8*x^2)^2. - Colin Barker, Sep 18 2018

EXAMPLE

Some solutions for n=4:

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

..2..3..0....2..3..2....3..3..0....3..0..3....3..0..3....3..2..0....2..0..1

..0..2..1....0..1..3....0..2..1....1..3..0....3..1..2....0..3..2....3..2..0

..1..3..2....2..0..3....1..0..2....0..1..3....2..3..0....1..0..3....3..1..2

CROSSREFS

Column 3 of A229479.

Sequence in context: A066563 A202865 A070808 * A157056 A180425 A140170

Adjacent sequences:  A229471 A229472 A229473 * A229475 A229476 A229477

KEYWORD

nonn

AUTHOR

R. H. Hardin, Sep 24 2013

STATUS

approved

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Last modified August 4 05:02 EDT 2021. Contains 346442 sequences. (Running on oeis4.)