Here’s another cute math problem. Does

\[ \sum_{m=1}^\infty\sum_{n=1}^\infty\frac{1}{m^2+n^2} \]

converge or diverge? I’ll post my solution in a day or two.

Here’s another cute math problem. Does

\[ \sum_{m=1}^\infty\sum_{n=1}^\infty\frac{1}{m^2+n^2} \]

converge or diverge? I’ll post my solution in a day or two.