Exercise 26/10

Question

• Write a function that gets an int n and creates a list with all the integers from 0 to n. Then, starting from 2, it removes from the list all the multiples of the list elements. The function returns the list with the remaining elements.

in the text of the problem it is indicated to remove the multiples but I did not understand which ones, of 2?

Answer 1

"removes from the list all the multiples of the list elements"

I suppose you have to remove the multiples of 2, then those of 3, then those of 5 then those of 7 and so on. Thus the final list should be just the prime numbers.

Answer 2

I think that the process is more or less: starting from 2, remove all the elements divisible by 2 in the list; then, do the same operation with, as a divisor, the number immediately next to 2 in the list; then with the number immediately next to this one and so on. It is quite clear that the left out numbers are only prime numbers up to N.