Below is an instruction that describes a task. Write a response that appropriately completes the request in French. Please answer in French.

### Instruction:
 Alex has 4 pens in the first week of a month. Every week her pen collection doubles. How many more pens will Alex have than Jane if Jane will have 16 pens after a month?


### Response:
 Si Alex a 4 stylos la première semaine d'un mois, elle aura 4*2=<<4*2=8>>8 stylos la deuxième semaine.
Après que sa collection de stylos double la troisième semaine, Alex aura 2*8 = 16 stylos.
Dans la dernière semaine du mois, Alex aura 2*16 = <<2*16=32>>32 stylos après sa collection de stylos.
Si Jane a 16 stylos après un mois, Alex aura 32 - 16 = <<32-16=16>>16 stylos de plus que Jane.