Reciprocal Of Some Euler Sums
Leroy Quet
qq-quet at mindspring.com
Mon Aug 16 16:11:42 CEST 2004
I posted the message below to sci.math, with no responses.
Maybe someone can extend the sequence.
Thanks.
-----
I was wondering about the Dirichlet sum:
sum{k=1 to oo} a(k)/k^r =
1/(sum{k=1 to oo} (sum{j=1 to k} 1/j) /k^r)
=
(for r =integer >= 2)
1/(zeta(r+1)(r/2 +1) -(1/2)sum{j=2 to r-1} zeta(j)zeta(r+1-j))
We have a(1) = 1,
and, for m >= 2,
a(m) = -sum{k|m,k>=2} (sum{j=1 to k} 1/j) a(m/k),
where sum{j=1 to k} 1/j = H(k), the k-th harmonic number.
We have the a-sequence (if I did not err):
1, -3/2, -11/6, 1/6, -137/60, 61/20,...
What is the closed-form (non-recursive form) for the terms of this
sequence?
thanks,
Leroy Quet
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