|
|
A229689
|
|
Number of defective 3-colorings of an n X 3 0..2 array connected horizontally and antidiagonally with exactly two mistakes, and colors introduced in row-major 0..2 order.
|
|
1
|
|
|
1, 43, 626, 6732, 62856, 539568, 4377888, 34105536, 257634432, 1899645696, 13735899648, 97733495808, 686049232896, 4760622968832, 32708331380736, 222789318524928, 1506002505596928, 10111798278291456, 67486591206162432
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
|
|
LINKS
|
|
|
FORMULA
|
Empirical: a(n) = 18*a(n-1) -108*a(n-2) +216*a(n-3) for n > 4.
Empirical: g.f. x -x^2*(43-148*x+108*x^2) / (6*x-1)^3. - R. J. Mathar, Sep 29 2013
|
|
EXAMPLE
|
Some solutions for n=3
..0..0..1....0..0..1....0..1..2....0..1..0....0..1..2....0..1..1....0..1..2
..2..1..2....2..1..2....0..1..0....2..0..2....1..2..0....0..2..1....1..2..1
..2..0..2....0..1..0....1..2..2....1..2..0....0..1..0....0..0..1....1..2..1
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|