We consider: $ $ a_{1}=c-1$ $ $ $ a_{n+1}= \frac{-n}{n+c \cdot \sqrt[n]{ln(n^{9876}+17)}}\cdot a_{n}, n\ge 1$ $ $ $ c\ge0$ $ I want to use Rabbe Test, because then in a simple way it comes out that the series is convergent for every $ c\ge0$ . However I have two doubts: 1) Raabe Test is for $ a_{n}>0$ , but if I do $ r_{n}=n(|\frac{a_{n}}{a_{n+1}}|-1)$ I knew that I must removing minus at $ n$ and then I can leave the module. Hovewer I’m not sure if it’s allowed. 2) If Raabe Test is a good way to do this task I knew only when my series is convergent, but I don’t knew when is absolutely convergent so the more I do not know if Raabe Test is a good idea.