Even in a truly random sequence, you could flip a coin 50 times and land on heads each time. You can also calculate the probability of that happening.
In a truly random sequence, every number has the same probability of being next.
In a less random sequence, some numbers are more likely than others. For example, in a binary sequence the next number could have a 10% chance of being 1, and 90% chance of being 0.
In a random sequence, there is a higher probability of getting a 1, and a lower probability of getting a zero. But that is only in comparison with a non-random sequence. Compared to the other numbers in the random sequence, each has the same probability of being next.