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A229632
Number of defective 3-colorings of an nX3 0..2 array connected horizontally, diagonally and antidiagonally with exactly two mistakes, and colors introduced in row-major 0..2 order
1
1, 40, 244, 1496, 8800, 50084, 277996, 1513104, 8106632, 42869740, 224232436, 1161920760, 5972173872, 30479422388, 154582269500, 779632820512, 3912450838808, 19545592617532, 97246103407556, 482032538140680
OFFSET
1,2
COMMENTS
Column 3 of A229637
LINKS
FORMULA
Empirical: a(n) = 15*a(n-1) -81*a(n-2) +185*a(n-3) -162*a(n-4) +60*a(n-5) -8*a(n-6) for n>7.
Empirical: g.f. x -4*x^2*(2*x-5)*(12*x^4-45*x^3+47*x^2-17*x+2) / (2*x^2-5*x+1)^3. - R. J. Mathar, Sep 29 2013
EXAMPLE
Some solutions for n=3
..0..1..1....0..1..0....0..0..1....0..1..2....0..0..1....0..1..0....0..1..1
..2..1..0....0..2..0....1..2..0....2..1..0....2..1..2....0..1..0....0..2..0
..0..1..0....2..1..2....0..2..1....0..1..1....0..1..2....1..2..2....0..1..2
CROSSREFS
Sequence in context: A068790 A073962 A267391 * A223426 A290127 A115170
KEYWORD
nonn
AUTHOR
R. H. Hardin, Sep 27 2013
STATUS
approved