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A229667 Number of defective 4-colorings of an nX3 0..3 array connected horizontally, antidiagonally and vertically with exactly two mistakes, and colors introduced in row-major 0..3 order 1
1, 61, 1555, 19805, 194575, 1673561, 13271403, 99602405, 718231671, 5024073665, 34312328499, 229845418733, 1515221386655, 9855527727977, 63373619492795, 403501000362805, 2547056875288967, 15956625712036945, 99294517974997251 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 3 of A229672

LINKS

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

FORMULA

Empirical: a(n) = 21*a(n-1) -171*a(n-2) +679*a(n-3) -1368*a(n-4) +1344*a(n-5) -512*a(n-6) for n>7.

Empirical: G.f. x -x^2*(-61-274*x+2419*x^2-3156*x^3-1744*x^4+3392*x^5) / (8*x^2-7*x+1)^3. - R. J. Mathar, Sep 29 2013

EXAMPLE

Some solutions for n=3

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

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

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

CROSSREFS

Sequence in context: A000507 A143011 A211213 * A242382 A017777 A113054

Adjacent sequences:  A229664 A229665 A229666 * A229668 A229669 A229670

KEYWORD

nonn

AUTHOR

R. H. Hardin, Sep 27 2013

STATUS

approved

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Last modified October 23 00:11 EDT 2021. Contains 348204 sequences. (Running on oeis4.)