A208813 Number of n-bead necklaces labeled with numbers -7..7 not allowing reversal, with sum zero and three times sum of squares <= n*(7)*(7+1).

1, 5, 37, 355, 3595, 41962, 486633, 5896400, 75009913, 947911584, 12153660815, 161974729738

Offset

1,2

Comments

Column 7 of A208814.

Links

Table of n, a(n) for n=1..12.

Example

Some solutions for n=6:
.-6...-5...-6...-4...-7...-4...-4...-5...-6...-4...-4...-3...-6...-3...-4...-4
.-1....4....0....5....4...-1....1....0....4...-4...-3...-3....4....2....1....0
..4...-4....5...-3....6....4...-1....7....2....5...-1...-1....0....2....1....2
..2....4...-5....5....1....0....1...-3....4....6....3....3....3....0....2...-1
.-4....0....2...-3...-2....0....4...-2...-4...-4....3...-3...-1...-1...-2....3
..5....1....4....0...-2....1...-1....3....0....1....2....7....0....0....2....0

Crossrefs

Sequence in context: A356848 A004208 A198077 * A112698 A234953 A344051

Adjacent sequences: A208810 A208811 A208812 * A208814 A208815 A208816

Keyword

nonn

Author

R. H. Hardin, Mar 01 2012

Status

approved