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A229681 Number of defective 3-colorings of an n X 4 0..2 array connected diagonally and antidiagonally with exactly two mistakes, and colors introduced in row-major 0..2 order. 1
0, 360, 10896, 186576, 2700432, 35485776, 437924880, 5169543120, 59031049104, 656886585168, 7159989801744, 76729919248080, 810700618461840, 8463178886657616, 87441690785378832, 895373932606109136 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Column 4 of A229685.
LINKS
FORMULA
Empirical: a(n) = 27*a(n-1) - 243*a(n-2) + 729*a(n-3) for n > 6.
Conjectures from Colin Barker, Jun 16 2017: (Start)
G.f.: 24*x^2*(15 + 49*x - 839*x^2 + 2007*x^3 - 1296*x^4) / (1 - 9*x)^3.
a(n) = 16*3^(2*n-7)*(-449 + 60*n + 256*n^2) for n > 3.
(End)
EXAMPLE
Some solutions for n=3:
0 1 1 0 0 0 1 2 0 1 0 2 0 0 0 1 0 1 1 0
2 2 0 1 1 1 1 1 2 1 2 2 0 2 2 2 0 0 0 2
1 1 0 1 2 2 2 0 2 1 1 0 1 1 1 2 2 2 1 2
CROSSREFS
Sequence in context: A056322 A056313 A192829 * A054648 A230684 A299955
KEYWORD
nonn
AUTHOR
R. H. Hardin, Sep 27 2013
STATUS
approved

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Last modified May 27 21:25 EDT 2024. Contains 372882 sequences. (Running on oeis4.)