Number of imprimitive (periodic) bracelets (or necklaces) with n red or blue beads such that the beads switch colors when bracelet is turned over.

A115121

Number of imprimitive (periodic) bracelets (or necklaces) with n red or blue beads such that the beads switch colors when bracelet is turned over.

Terms

    a(0) =0a(1) =1a(2) =1a(3) =2a(4) =1a(5) =3a(6) =1a(7) =4a(8) =2a(9) =5a(10) =1a(11) =11a(12) =1a(13) =11a(14) =5a(15) =22a(16) =1a(17) =37a(18) =1a(19) =64a(20) =11a(21) =95a(22) =1a(23) =210a(24) =4a(25) =317a(26) =30a(27) =625a(28) =1a(29) =1160

External references