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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. 1
6, 27, 171, 1089, 6939, 44217, 281763, 1795473, 11441259, 72906921, 464583411, 2960456193, 18864859707, 120212193177, 766025913411, 4881332621169, 31105224694539, 198211242377097, 1263057797861523, 8048559615522273 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 2 of A223556.

LINKS

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

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

EXAMPLE

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

CROSSREFS

Cf. A223556.

Sequence in context: A144013 A318565 A092854 * A289022 A060977 A267630

Adjacent sequences:  A223554 A223555 A223556 * A223558 A223559 A223560

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 22 2013

STATUS

approved

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Last modified March 29 05:39 EDT 2020. Contains 333105 sequences. (Running on oeis4.)