Is $$\sum_{n=3}^\infty \frac{1}{n^2 \log^3 n}$$ absolutely convergent?
Using comparison test, since $n$ is greater than or equal to 3: $$\frac{1}{n^2 \log^3 n} \leq \frac{1}{n^2}$$
And, we know $$\sum_{n=3}^\infty \frac{1}{n^2}$$ converges by p-test.
Therefore, $$\sum_{n=3}^\infty \frac{1}{n^2 \log^3 n}$$ converges absolutely.