A208812 Number of n-bead necklaces labeled with numbers -6..6 not allowing reversal, with sum zero and three times sum of squares <= n*(6)*(6+1).

1, 4, 29, 236, 2095, 20409, 209793, 2220143, 23933783, 264637987, 2967244283, 33695174581, 387241027611

Offset

1,2

Comments

Column 6 of A208814:

Links

Table of n, a(n) for n=1..13.

Example

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

Crossrefs

Sequence in context: A140526 A151343 A371743 * A291103 A125808 A367752

Adjacent sequences: A208809 A208810 A208811 * A208813 A208814 A208815

Keyword

nonn

Author

R. H. Hardin, Mar 01 2012

Status

approved