The random object outputs a pseudo-randomly chosen integer. The range of possible numbers is determined by the number received in the right inlet (or specified as a typed-in argument). Each time random receives a bang, it will output one of n possible numbers, ranging from 0 to n-1. Because each number has an equal probability of occurring each time, there’s a possibility that repetitions will occur. If you wish to prevent repetitions there are two approaches.
If you want to make an oscillator with unstable pitch, you can modulate the pitch of the oscillator using a noise signal as an exponent with a base of 2, and applying that as a multiplier to vary the fundamental frequency. In that way, when the noise ranges from -1 to +1, it will cause a pitch variation of ±1 octave, whatever the fundamental frequency of the oscillator. Divide the amplitude of the noise by 1200 if you want to be able to represent pitch variation in cents.