Number of n-bead necklaces labeled with numbers -1..1 allowing reversal, with sum zero with no three beads in a row equal.

A209337

Number of n-bead necklaces labeled with numbers -1..1 allowing reversal, with sum zero with no three beads in a row equal.

Terms

    a(0) =1a(1) =2a(2) =1a(3) =4a(4) =5a(5) =14a(6) =21a(7) =51a(8) =102a(9) =249a(10) =555a(11) =1358a(12) =3201a(13) =7890a(14) =19232a(15) =47869a(16) =118955a(17) =298875a(18) =752039a(19) =1904621a(20) =4835666a(21) =12330144a(22) =31521037a(23) =80836979a(24) =207803455a(25) =535535393a(26) =1383064966a(27) =3579351724a(28) =9280561947

External references