A223693 Petersen graph (8,2) coloring a rectangular array: number of 2 X n 0..15 arrays where 0..15 label nodes of a graph with edges 0,1 0,8 8,14 8,10 1,2 1,9 9,15 9,11 2,3 2,10 10,12 3,4 3,11 11,13 4,5 4,12 12,14 5,6 5,13 13,15 6,7 6,14 7,0 7,15 and every array movement to a horizontal or antidiagonal neighbor moves along an edge of this graph.

256, 432, 2304, 12384, 66816, 361440, 1958400, 10622304, 57652992, 313044192, 1700213760, 9235776096, 50175150336, 272604245472, 1481134892544, 8047630034784, 43726888532736, 237593019598560, 1290986302371840

Offset

1,1

Comments

Row 2 of A223692.

Links

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

Formula

Empirical: a(n) = 8*a(n-1) - 11*a(n-2) - 16*a(n-3) for n>4.

Empirical g.f.: 16*x*(16 - 101*x + 104*x^2 + 175*x^3) / (1 - 8*x + 11*x^2 + 16*x^3). - Colin Barker, Aug 22 2018

Example

Some solutions for n=3:
..2.10..2....6.14.12....6..7..0...13.11..3....4..5..6....1..9..1...11.13..5
..2..3.11....8.10..2....6..7..0....3.11.13....4..5.13....1..0..8....5..4..3

Crossrefs

Cf. A223692.

Sequence in context: A115176 A299156 A221259 * A223064 A206206 A206199

Adjacent sequences: A223690 A223691 A223692 * A223694 A223695 A223696

Keyword

nonn

Author

R. H. Hardin, Mar 25 2013

Status

approved