|
|
A209066
|
|
Number of n-bead necklaces labeled with numbers -1..1 not allowing reversal, with sum zero and avoiding the pattern z z+1 z+2.
|
|
1
|
|
|
1, 2, 2, 5, 8, 19, 39, 95, 223, 554, 1373, 3493, 8906, 23016, 59805, 156588, 412082, 1090443, 2897828, 7733433, 20712345, 55661171, 150031505, 405533996, 1098949141, 2985066757, 8125987470, 22165517960, 60575472281, 165835969094
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
|
|
LINKS
|
|
|
EXAMPLE
|
Some solutions for n=6:
.-1...-1...-1...-1....0...-1...-1...-1...-1...-1...-1...-1...-1...-1...-1...-1
..1....0...-1...-1....0...-1....0....1....0...-1....1....0....1....0...-1....0
..0...-1....1....1....0....0....0...-1...-1....1....0....0...-1....0....1....0
.-1....1....0...-1....0....0....1....1....1....0....0....0....1....1....1...-1
..1....0....0....1....0....1...-1...-1....1....1....0....1....0....0...-1....1
..0....1....1....1....0....1....1....1....0....0....0....0....0....0....1....1
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|