You, too, must have seen one repeat or other inside series. While we are watching the Electronic reader boards the most visible ones are inside Black or Red. But any other group of 18 numbers shows similar patterns when it comes to repeats of single numbers. Have you actually looked at the probabilities connected to such repeats?
It should not be too complicated. With my cheap calculator with 12 digits I find the chance of a no Straight Up repeat within just two Reds in a row: 17/18 = 0.94444444444. All you have do if you want to find the probability for a repeat is to subtract the result from 1.
Accordingly the probability of no plein repeat in a EC sequence with three spins is 17/18 X 16/18.
And so forth and so on.
HIGH OR LOW SERIES have the advantage it is easy to find the probabilities for street repeats or
split repeats. There are just six streets in 1-18. SO IN A LOW SERIES OF SIX SPINS THERE THE PROBABILTY OF NO STREET REPEAT IS 5/6 X 4/6 X 3/6 X 2/6 X 1/6 = 0.01543209876