A223368 6 X 6 X 6 triangular graph coloring a rectangular array: number of n X 6 0..20 arrays where 0..20 label nodes of the fully triangulated graph and every array movement to a horizontal or vertical neighbor moves along an edge of this graph.

45984, 20537766, 11391019146, 6710970374274, 4058501783492178, 2480736960312897168, 1524391185435213940170, 939167584646744478258996, 579454062205580451233813394, 357802181014544893364679825516

Offset

1,1

Comments

Column 6 of A223370.

Links

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

Example

Some solutions for n=3
..1..0..2..5..2..0....1..0..2..4..5..8....1..0..2..4..2..5....1..0..2..4..5..9
..0..2..4..2..4..2....0..2..0..1..2..4....0..2..1..3..1..2....0..2..4..5..4..5
..1..0..2..5..2..5....1..0..1..2..4..1....1..0..2..1..2..4....1..0..1..4..8..9
Vertex neighbors:
0 -> 1 2
1 -> 0 2 3 4
2 -> 0 1 4 5
3 -> 1 4 6 7
4 -> 1 2 3 5 7 8
5 -> 2 4 8 9
6 -> 3 7 10 11
7 -> 3 4 6 8 11 12
8 -> 4 5 7 9 12 13
9 -> 5 8 13 14
10 -> 6 11 15 16
11 -> 6 7 10 12 16 17
12 -> 7 8 11 13 17 18
13 -> 8 9 12 14 18 19
14 -> 9 13 19 20
15 -> 10 16
16 -> 10 11 15 17
17 -> 11 12 16 18
18 -> 12 13 17 19
19 -> 13 14 18 20
20 -> 14 19

Crossrefs

Cf. A223370.

Sequence in context: A031635 A159725 A210306 * A061405 A061529 A115939

Adjacent sequences: A223365 A223366 A223367 * A223369 A223370 A223371

Keyword

nonn

Author

R. H. Hardin, Mar 19 2013

Status

approved