cp's OEIS Frontend

A254081 Number of primitive (=aperiodic) n-bead necklaces with colored beads of exactly 9 different colors.

%I A254081 #4 Jan 25 2015 10:18:09
%S A254081 40320,1632960,38102400,673596000,10035083520,133102569600,
%T A254081 1623972430080,18615386790000,203401119841920,2140495978400640,
%U A254081 21860934514473600,217932712305073920,2130148393318725120,20485620162998625600,194378546540211264000,1823813323809879402000
%N A254081 Number of primitive (=aperiodic) n-bead necklaces with colored beads of exactly 9 different colors.
%H A254081 Alois P. Heinz, <a href="/A254081/b254081.txt">Table of n, a(n) for n = 9..1000</a>
%p A254081 with(numtheory):
%p A254081 b:= proc(n, k) option remember; `if`(n=0, 1,
%p A254081       add(mobius(n/d)*k^d, d=divisors(n))/n)
%p A254081     end:
%p A254081 a:= n-> add(b(n, 9-j)*binomial(9, j)*(-1)^j, j=0..9):
%p A254081 seq(a(n), n=9..30);
%Y A254081 Column k=9 of A254040.
%K A254081 nonn
%O A254081 9,1
%A A254081 _Alois P. Heinz_, Jan 25 2015