A208801 Number of n-bead necklaces labeled with numbers -4..4 allowing reversal, with sum zero and three times sum of squares <= n*(4)*(4+1).

1, 3, 8, 50, 239, 1746, 11557, 82577, 648289, 4806475, 36522073, 300186549, 2339239465, 18355175927, 154771130241, 1236373902645, 9941856371385, 85100077549321, 691573737441489, 5648994401150475

Offset

1,2

Comments

Column 4 of A208805.

Links

Andrew Howroyd, Table of n, a(n) for n = 1..50

Example

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

Crossrefs

Sequence in context: A338439 A005444 A222684 * A019044 A265961 A019035

Adjacent sequences: A208798 A208799 A208800 * A208802 A208803 A208804

Keyword

nonn

Author

R. H. Hardin, Mar 01 2012

Extensions

a(15)-a(20) from Andrew Howroyd, Mar 02 2017

Status

approved