Let's start with the second.
You said you tried Leibniz and that it gave you nothing.
From the formula there's a pretty good match with Leibniz's test, so let's investigate.
Can you find ?
I have two series:
. I wanted to 'group' terms but I had a problem with idices.
I tried the Leibniz's, Dirichlet's, Abel's tests but they gave me nothing. Any hints how to cope with them?