A223369 - OEIS

%I #4 Mar 19 2013 16:37:59

%S 221760,250834914,365447949798,573055927043172,928457167048336590,

%T 1524391185435213940170,2520297393549555690831036,

%U 4179551352031701135658304214,6944490071035753511344864688838

%N 6X6X6 triangular graph coloring a rectangular array: number of nX7 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

%C Column 7 of A223370

%H R. H. Hardin, <a href="/A223369/b223369.txt">Table of n, a(n) for n = 1..71</a>

%e Some solutions for n=3

%e ..0..1..0..1..3..6..3....0..1..0..2..5..2..0....0..1..0..2..5..2..5

%e ..1..0..2..0..1..3..1....1..0..2..4..2..4..1....1..0..2..0..2..0..2

%e ..0..2..0..1..4..7..4....0..2..0..2..5..8..4....0..2..0..1..0..2..4

%e Vertex neighbors:

%e 0 -> 1 2

%e 1 -> 0 2 3 4

%e 2 -> 0 1 4 5

%e 3 -> 1 4 6 7

%e 4 -> 1 2 3 5 7 8

%e 5 -> 2 4 8 9

%e 6 -> 3 7 10 11

%e 7 -> 3 4 6 8 11 12

%e 8 -> 4 5 7 9 12 13

%e 9 -> 5 8 13 14

%e 10 -> 6 11 15 16

%e 11 -> 6 7 10 12 16 17

%e 12 -> 7 8 11 13 17 18

%e 13 -> 8 9 12 14 18 19

%e 14 -> 9 13 19 20

%e 15 -> 10 16

%e 16 -> 10 11 15 17

%e 17 -> 11 12 16 18

%e 18 -> 12 13 17 19

%e 19 -> 13 14 18 20

%e 20 -> 14 19

%K nonn

%O 1,1

%A _R. H. Hardin_ Mar 19 2013