,
where 
are
the basic probabilities of that symbol occurring on the reels respectively. 16-reel slot machines
2. Case B – different numbers of stops and symbol distributions on the reels
2.7 A specific symbol at least three times on a payline
The probability of this event is
,
where are
the basic probabilities of that symbol occurring on the reels respectively.
2.9 A specific symbol four times or another specific symbol at least three times on a payline
The probability of this event is
,
where 
are
the basic probabilities of the two symbols occurring on the reels respectively.
2.10 A specific symbol four times or any combination of that symbol with another specific symbol on a payline
The probability of this event is
,
where are
the basic probabilities of the two symbols occurring on the reels respectively.