A generalization of the question of Sierpiński on geometric progressions.
Let a, b, c be relatively prime positive integers such that . Jeśmanowicz conjectured in 1956 that for any given positive integer n the only solution of in positive integers is x=y=z=2. If n=1, then, equivalently, the equation , for integers u>v>0, has only the solution x=y=z=2. We prove that this is the case when one of u, v has no prime factor of the form 4l+1 and certain congruence and inequality conditions on u, v are satisfied.
We show that the system of equations , where is a triangular number, has infinitely many solutions in integers. Moreover, we show that this system has a rational three-parameter solution. Using this result we show that the system has infinitely many rational two-parameter solutions.