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.

2, 20, 140, 863, 4962, 27313, 145932, 763031, 3924694, 19928429, 100145056, 498967875, 2468341930, 12136538329, 59362244596, 289033801519, 1401690320766, 6773621702213, 32630424771912, 156746889564187, 751052250017618

Offset

1,1

Links

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

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

Column 3 of A229460.

Sequence in context: A093647 A244887 A279112 * A003490 A081006 A003481

Adjacent sequences: A229451 A229452 A229453 * A229455 A229456 A229457

Keyword

nonn

Author

R. H. Hardin, Sep 24 2013

Status

approved