def crible(n):
"""
Renvoie un tableau contenant tous les nombres premiers plus petits que N
"""
premiers = []
tab = [True] * n
tab[0], tab[1] = False, False
for i in range(2, n):
if tab[i] == True:
premiers.append(i)
for multiple in range(2*i, n, i):
tab[multiple] = False
return premiers
assert crible(40) == [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37]