A294650 a(n) = denominator(A206369(n))/n.

1, 2, 3, 4, 5, 3, 7, 8, 9, 5, 11, 2, 13, 7, 15, 16, 17, 18, 19, 5, 7, 11, 23, 12, 25, 13, 27, 14, 29, 15, 31, 32, 33, 17, 35, 12, 37, 19, 13, 2, 41, 7, 43, 22, 45, 23, 47, 24, 49, 50, 51, 13, 53, 27, 11, 28, 19, 29, 59, 5, 61, 31, 3, 64, 65, 33, 67, 17, 69, 35

Offset: 1

Author

Michel Marcus, Nov 06 2017

Keywords

• nonn
• frac

Links

• Michel Marcus, Table of n, a(n) for n = 1..10000
• László Tóth, A survey of the alternating sum-of-divisors function, arXiv:1111.4842 [math.NT], 2011-2014.

Crossrefs

Cf. A127724 (k-imperfect), A206369, A294649 (numerator).

A225680 is a subsequence (on squarefree indices). - Michel Marcus, Dec 22 2017

Programs

Mathematica

(* b = A209369 *) b[n_] := n*DivisorSum[n, LiouvilleLambda[#]/# &];
a[n_] := Denominator[b[n]/n];
Array[a, 100] (* Jean-François Alcover, Dec 04 2017 *)

PARI

rhope(p, e) = my(s=1); for(i=1, e, s=s*p + (-1)^i); s;
rho(n) = my(f=factor(n)); prod(i=1, #f~, rhope(f[i, 1], f[i, 2]));
a(n) = denominator(rho(n)/n);