n = 20 primes = [i for i in range(2, n + 1) if all(i%j != 0 for j in range(2, int(i ** 0.5) + 1))] print(primes)
>>> [x for x in range(2, 20) if all(x % y != 0 for y in range(2, x))] [2, 3, 5, 7, 11, 13, 17, 19]