repeat-on-final-keystroke

repeat-on-final-keystroke is a variable defined in `repeat.el'.
Its value is

t

Documentation:
Allow `repeat' to re-execute for repeating lastchar of a key sequence.
If this variable is t, `repeat' determines what key sequence
it was invoked by, extracts the final character of that sequence, and
re-executes as many times as that final character is hit; so for example
if `repeat' is bound to C-x z, typing C-x z z z repeats the previous command
3 times. If this variable is a sequence of characters, then re-execution
only occurs if the final character by which `repeat' was invoked is a
member of that sequence. If this variable is nil, no re-execution occurs.

You can customize this variable.