A223557 Petersen graph (3,1) coloring a rectangular array: number of 2 X n 0..5 arrays where 0..5 label nodes of a graph with edges 0,1 0,3 3,5 3,4 1,2 1,4 4,5 2,0 2,5 and every array movement to a horizontal or antidiagonal neighbor moves along an edge of this graph, with the array starting at 0.

6, 27, 171, 1089, 6939, 44217, 281763, 1795473, 11441259, 72906921, 464583411, 2960456193, 18864859707, 120212193177, 766025913411, 4881332621169, 31105224694539, 198211242377097, 1263057797861523, 8048559615522273

Offset: 1

Author

R. H. Hardin, Mar 22 2013

Keywords

• nonn

Comments

Row 2 of A223556.

Examples

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

Links

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

Crossrefs

Cf. A223556.

Formula

Empirical: a(n) = 7*a(n-1) - 4*a(n-2) for n>3.

Empirical g.f.: 3*x*(2 - x)*(1 - 2*x) / (1 - 7*x + 4*x^2). - Colin Barker, Aug 21 2018