A223239 3-loop graph coloring a rectangular array: number of n X n 0..6 arrays where 0..6 label nodes of a graph with edges 0,1 1,2 2,0 0,3 3,4 4,0 0,5 5,6 6,0 and every array movement to a horizontal or vertical neighbor moves along an edge of this graph

7, 102, 11538, 5336844, 22029652542, 372027916726176, 55925027353114184220, 34340768547284823444042060, 187665945665214485110913868661962, 4188970054368199574776535077321295822220

Offset

1,1

Comments

Diagonal of A223247

Links

R. H. Hardin, Table of n, a(n) for n = 1..11

Example

Some solutions for n=3
..0..1..0....1..0..6....4..0..6....3..0..5....2..0..1....4..0..5....2..0..4
..1..0..3....0..3..0....0..4..0....0..5..0....0..6..0....0..6..0....0..3..0
..0..3..4....1..0..6....5..0..3....4..0..6....6..0..5....6..0..2....6..0..3

Crossrefs

Sequence in context: A358159 A203356 A346719 * A140633 A142400 A032460

Adjacent sequences: A223236 A223237 A223238 * A223240 A223241 A223242

Keyword

nonn

Author

R. H. Hardin Mar 18 2013

Status

approved