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
Keywords
Examples
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
Links
- Andrew Howroyd, Table of n, a(n) for n = 1..50
Crossrefs
Column 6 of A209032.
Extensions
a(14)-a(22) from Andrew Howroyd, Mar 12 2017