Number of n-bead necklaces labeled with numbers -2..2 not allowing reversal, with sum zero.

A208591

Number of n-bead necklaces labeled with numbers -2..2 not allowing reversal, with sum zero.

Terms

    a(0) =1a(1) =3a(2) =7a(3) =23a(4) =77a(5) =297a(6) =1163a(7) =4783a(8) =20041a(9) =85735a(10) =371955a(11) =1634429a(12) =7254547a(13) =32486709a(14) =146576693a(15) =665720447a(16) =3041096613a(17) =13963651875a(18) =64410421307a(19) =298331882891

External references