Question 49
Petrik uses the computer program "Three", which converts the numbers written on the display. For one application of this program Petrik chooses 5 numbers from the written ones, and the program increases each of these 5 numbers in 3 times. At the beginning, the following 20 numbers are written on the display: 1, $3^1$, $3^2$, ..., $3^{19}$. What smallest number of times does Petrik have to use the program to be able to get a set of equal numbers on the display?