A223600 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, diagonal or antidiagonal neighbor moves along an edge of this graph.

256, 256, 1504, 6736, 32768, 156592, 755200, 3643024, 17608064, 85179184, 412367104, 1997306896, 9677417600, 46900761520, 227339596288, 1102103488912, 5343259128704, 25906912147504, 125615423519488, 609091866864400

Offset: 1

Author

R. H. Hardin, Mar 23 2013

Keywords

• nonn

Comments

Row 2 of A223599.

Examples

			Some solutions for n=3:
..2..3..4...11..3..4....0..8.14...15..7..0...15..9..1....3..4..3....9.15..7
.11..3..2....4..3..4...10..8.10....0..7..0...11..9.15....5..4..5...13.15..9
		

Links

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

Crossrefs

Cf. A223599.

Formula

Empirical: a(n) = 6*a(n-1) + 3*a(n-2) - 42*a(n-3) - 8*a(n-4) + 48*a(n-5) for n>6.

Empirical g.f.: 16*x*(16 - 80*x - 50*x^2 + 481*x^3 + 40*x^4 - 456*x^5) / ((1 + 2*x)*(1 - 8*x + 13*x^2 + 16*x^3 - 24*x^4)). - Colin Barker, Aug 21 2018