|
|
A229454
|
|
Number of defective 3-colorings of an n X 3 0..2 array connected horizontally and vertically with exactly one mistake and colors introduced in row-major 0..2 order.
|
|
1
|
|
|
2, 20, 140, 863, 4962, 27313, 145932, 763031, 3924694, 19928429, 100145056, 498967875, 2468341930, 12136538329, 59362244596, 289033801519, 1401690320766, 6773621702213, 32630424771912, 156746889564187, 751052250017618
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
LINKS
|
|
|
FORMULA
|
Empirical: a(n) = 10*a(n-1) - 29*a(n-2) + 20*a(n-3) - 4*a(n-4).
Empirical g.f.: x*(2 - 2*x^2 + 3*x^3) / (1 - 5*x + 2*x^2)^2. - Colin Barker, Sep 17 2018
|
|
EXAMPLE
|
Some solutions for n=3:
..0..0..1....0..1..0....0..1..2....0..1..0....0..1..2....0..1..2....0..1..0
..2..1..0....0..2..1....2..0..1....1..0..1....1..2..1....2..2..0....2..1..2
..1..0..2....2..1..0....1..2..1....0..2..2....2..0..0....1..0..2....1..0..1
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|