This question is related to the following two formulas for ζ(s).
(1) ζ(s)=11−21−s∞∑n=012n+1n∑k=0(−1)k(nk)(k+1)s,s≠1(see ref(1) and formula (21) at ref(2))
(2) ζ(s)=1s−1∞∑n=01n+1n∑k=0(−1)k(nk)(k+1)s−1(see ref(1) and formula (22) at ref(2))
Formula (1) above is claimed to converge for s≠1 at ref(2), but note that 11−21−s exhibits a complex infinity at s=1+i2πjlog(2) where j∈Z which seems consistent with the convergence claim at ref(1).
Question (1): Is it true that formula (1) converges for s≠1+i2πjlog(2) where j∈Z versus s≠1? Or is there an argument about zeros and poles cancelling each other out when formula (1) for ζ(s) is evaluated at s=1+i2πjlog(2) where j∈Z similar to the argument for the convergence of the right side of the functional equation \zeta(s)=2^s π^{s−1}\sin\left(\frac{π\,s}{2}\right)\,\Gamma(1−s)\,\zeta(1−s) at positive integer values of s (e.g. see Using the functional equation of the Zeta function to compute positive integer values)?
Since originally posting question (1) above, I discovered the following Wikipedia article which I believe provides some insight.
Wikipedia Article: Landau's problem with \zeta(s)=\frac{\eta(s)}{0} and solutions
Formula (2) above is claimed to be globally convergent, but seems to exhibit a significant divergence (see Figure (1) below).
Question (2): Is there an error in formula (2), or is there a conditional convergence requirement associated with formula (2) when the outer series is evaluated for a finite number of terms?
ref(1): Wikipedia Article: Riemann zeta function, Representations, Globally convergent series
12/10/2018 Update:
I'm now wondering if formula (2) for \zeta(s) is perhaps only valid for s\in\mathbb{Z}.
The following plot illustrates formula (2) for \zeta(s) evaluated for the first 100 terms.
Figure (1): Illustration of Formula (2) for \zeta(s)
The following discrete plot illustrates formula (2) for \zeta(s) minus \zeta(s) where formula (2) is evaluated for the first 100 terms in blue and the first 1000 terms in orange.
Figure (2): Discrete Plot of Formula (2) for \zeta(s) minus \zeta(s)
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