A209030 Number of n-bead necklaces labeled with numbers -6..6 allowing reversal, with sum zero and first differences in -6..6.

1, 4, 10, 60, 358, 2798, 22249, 186765, 1596162, 13907330, 122758794, 1096122478, 9880366438, 89796245827, 821927851286, 7570508171686, 70115797179348, 652594351781036, 6100765243003922, 57259681174637899, 539353919732122101, 5097036850039818860

Offset

1,2

Links

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

Example

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

Crossrefs

Column 6 of A209032.

Sequence in context: A328036 A222675 A328155 * A220824 A124724 A362705

Adjacent sequences: A209027 A209028 A209029 * A209031 A209032 A209033

Keyword

nonn

Author

R. H. Hardin, Mar 04 2012

Extensions

a(14)-a(22) from Andrew Howroyd, Mar 12 2017

Status

approved