A233258 Number of 3 X n 0..5 arrays with no element x(i,j) adjacent to itself or value 5-x(i,j) horizontally or antidiagonally, top left element zero, and 1 appearing before 2 3 and 4, and 2 appearing before 3 in row major order (unlabelled 6-colorings with no clashing color pairs).

11, 136, 4672, 166400, 6049792, 220626944, 8050180096, 293762760704, 10720053821440, 391200251052032, 14275841005453312, 520959990903603200, 19011091850007150592, 693760794065113186304, 25317011997007519154176

Offset

1,1

Links

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

Formula

Empirical: a(n) = 48*a(n-1) - 448*a(n-2) + 1024*a(n-3) for n>5.

Empirical g.f.: x*(11 - 392*x + 3072*x^2 - 8192*x^3 + 16384*x^4) / ((1 - 8*x)*(1 - 40*x + 128*x^2)). - Colin Barker, Oct 11 2018

Example

Some solutions for n=3:
..0..1..5....0..1..5....0..1..2....0..1..2....0..1..2....0..1..2....0..1..2
..5..2..5....5..2..0....3..1..3....0..4..5....2..5..3....3..1..5....5..1..2
..1..3..5....4..2..0....5..1..2....0..2..4....1..0..2....5..4..3....5..4..0

Crossrefs

Row 3 of A233256.

Sequence in context: A024143 A057718 A123800 * A262382 A142895 A232180

Adjacent sequences: A233255 A233256 A233257 * A233259 A233260 A233261

Keyword

nonn

Author

R. H. Hardin, Dec 06 2013

Status

approved