Animation Sequence (Modify or reversing frames order)

Hello !
Is it possible to change the frames order for the animation ?
Example, right now it's animating frames on the playback window like so : 1 2 3 - 1 2 3 : First frame, Second Frame and Third frame then loop from start again. 
But I would like to change for something like : 1 2 3 2 - 1 2 3 2 without creating a fourth frame identical to the second one.
In other words : after finishing the sequence, going backward.