A229455 Number of defective 3-colorings of an n X 4 0..2 array connected horizontally and vertically with exactly one mistake and colors introduced in row-major 0..2 order.

6, 84, 863, 7940, 68790, 573342, 4651079, 36985536, 289643385, 2240964186, 17168776578, 130470758748, 984730068189, 7389045257436, 55166274822951, 410065744877280, 3036389212951326, 22406600046050874, 164842346594552499

Offset

1,1

Links

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

Formula

Empirical: a(n) = 18*a(n-1) - 111*a(n-2) + 282*a(n-3) - 333*a(n-4) + 180*a(n-5) - 36*a(n-6) for n>7.

Empirical g.f.: x*(6 - 24*x + 17*x^2 + 38*x^3 - 27*x^4 - 12*x^5 + 8*x^6) / (1 - 9*x + 15*x^2 - 6*x^3)^2. - Colin Barker, Sep 17 2018

Example

Some solutions for n=3:
..0..1..0..1....0..1..0..1....0..1..2..1....0..1..1..2....0..1..2..1
..2..0..1..0....2..0..1..2....2..0..1..2....1..2..0..1....1..0..1..0
..0..1..2..2....2..1..2..1....1..2..2..0....2..0..1..2....2..0..2..1

Crossrefs

Column 4 of A229460.

Sequence in context: A119576 A371471 A098982 * A212701 A248338 A144514

Adjacent sequences: A229452 A229453 A229454 * A229456 A229457 A229458

Keyword

nonn

Author

R. H. Hardin, Sep 24 2013

Status

approved