Problems 1641-1650

Q1647 A monk visits $t$ temples and burns a number of incense sticks, the same number at each temple. The temples are located on different islands in a magic lake and he visits them by boat. The lake doubles the number of sticks he holds each time he reaches an island. At the end of the day he has burnt all his incense sticks. What is the smallest number of incense sticks that the monk could initially have had?