login
A223417
3-level binary fanout graph coloring a rectangular array: number of nX1 0..6 arrays where 0..6 label nodes of a graph with edges 0,1 1,3 1,4 0,2 2,5 2,6 and every array movement to a horizontal or vertical neighbor moves along an edge of this graph
1
7, 12, 26, 48, 104, 192, 416, 768, 1664, 3072, 6656, 12288, 26624, 49152, 106496, 196608, 425984, 786432, 1703936, 3145728, 6815744, 12582912, 27262976, 50331648, 109051904, 201326592, 436207616, 805306368, 1744830464, 3221225472
OFFSET
1,1
COMMENTS
Column 1 of A223423
LINKS
FORMULA
Empirical: a(n) = 4*a(n-2) for n>3
EXAMPLE
Some solutions for n=3
..5....0....5....3....3....0....3....4....0....0....1....2....6....1....2....0
..2....2....2....1....1....1....1....1....2....1....3....0....2....4....5....1
..0....6....6....4....3....4....0....3....0....3....1....1....5....1....2....0
CROSSREFS
Sequence in context: A273307 A093025 A104584 * A224699 A078575 A220036
KEYWORD
nonn
AUTHOR
R. H. Hardin Mar 20 2013
STATUS
approved