Unsolved Problems

What is the least prime $p$ such that there are integers $a, k_1, k_2, k_3$ with $\prod_{i=1}^{k_1} (a+i) \equiv \prod_{i=1}^{k_2} (a+k_1+i) \equiv \p...

What is the least positive odd number not of the form $\pm p^a \pm 2^b$, where $p$ is an odd prime?...