A229530 Number of defective 3-colorings of an n X 4 0..2 array connected horizontally, diagonally and antidiagonally with exactly one mistake, and colors introduced in row-major 0..2 order.

6, 36, 361, 3064, 24344, 185808, 1379512, 10036352, 71892488, 508702512, 3563926872, 24764330720, 170893859240, 1172387842960, 8002259515128, 54379352988992, 368101566941512, 2483167144168432, 16699758317833368

Offset

1,1

Links

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

Formula

Empirical: a(n) = 14*a(n-1) - 57*a(n-2) + 56*a(n-3) - 16*a(n-4) for n>5.

Empirical g.f.: x*(6 - 48*x + 199*x^2 - 274*x^3 + 105*x^4) / (1 - 7*x + 4*x^2)^2. - Colin Barker, Sep 18 2018

Example

Some solutions for n=4:
..0..1..0..2....0..1..0..2....0..1..2..1....0..1..0..1....0..1..0..2
..0..1..0..1....0..2..0..1....2..1..0..1....0..2..0..2....0..2..0..1
..0..2..0..1....0..1..0..2....2..1..0..2....1..2..1..0....0..1..2..1
..1..1..0..2....0..1..2..1....0..1..2..1....1..2..1..0....2..1..0..1

Crossrefs

Column 4 of A229534.

Sequence in context: A370752 A108733 A350525 * A265474 A277474 A137889

Adjacent sequences: A229527 A229528 A229529 * A229531 A229532 A229533

Keyword

nonn

Author

R. H. Hardin, Sep 25 2013

Status

approved