Number of primitive (aperiodic, or Lyndon) 3-asymmetric rhythm cycles: ones having no nontrivial shift automorphism. 3-asymmetric rhythm cycles (A115115): binary necklaces of length 3n subject to the restriction that for any k if the k-th bead is of color 1 then the (k+n)-th and (k+2n)-th beads (modulo 3n) are of color 0.

A115117

Number of primitive (aperiodic, or Lyndon) 3-asymmetric rhythm cycles: ones having no nontrivial shift automorphism. 3-asymmetric rhythm cycles (A115115): binary necklaces of length 3n subject to the restriction that for any k if the k-th bead is of color 1 then the (k+n)-th and (k+2n)-th beads (modulo 3n) are of color 0.

Terms

    a(0) =1a(1) =2a(2) =7a(3) =20a(4) =68a(5) =224a(6) =780a(7) =2720a(8) =9709a(9) =34918a(10) =127100a(11) =465920a(12) =1720740a(13) =6390930a(14) =23860928a(15) =89477120a(16) =336860180a(17) =1272578048a(18) =4822419420a(19) =18325176316a(20) =69810262080a(21) =266548209850

External references