login
Number of aperiodic bracelets (or necklaces) with n red and blue beads such that the beads switch colors when bracelet is turned over.
2

%I #9 Aug 28 2019 08:15:55

%S 1,1,3,7,20,51,154,460,1476,4860,16544,57321,202059,720370,2593470,

%T 9408000,34350506,126108252,465200332,1723341185,6408356052,

%U 23911255544,89495909408,335916703284,1264114452975,4768464107355

%N Number of aperiodic bracelets (or necklaces) with n red and blue beads such that the beads switch colors when bracelet is turned over.

%H <a href="/index/Br#bracelets">Index entries for sequences related to bracelets</a>

%F Moebius transform of A006080(n+1).

%t a[n_] := Sum[MoebiusMu[n/d] A006080[d + 1], {d, Divisors[n]}];

%t Array[a, 26] (* _Jean-François Alcover_, Aug 28 2019 *)

%K nonn

%O 1,3

%A _Christian G. Bower_, Dec 13 2001