3 p * q * r 
  5 p * q * r * p * r 
  7 p * q * r * p * r * p * r 
 11 p * q * r * p * q * r * p * q * r * p * r 
 13 p * q * r * p * q * r * p * r * p * q * r * p * r 
 14 p * q * r * p * q * r * p * q * r * p * q * r * p * r 
 16 p * q * r * p * q * r * p * q * r * p * r * p * q * r * p * r 
 17 p * q * r * p * q * r * p * q * r * p * q * r * p * q * r * p * r 
 17 p * q * r * p * r * p * q * r * p * r * p * q * r * p * r * p * r 
 18 p * q * r * p * q * r * p * r * p * q * r * p * r * p * q * r * p * r 
 19 p * q * r * p * q * r * p * q * r * p * q * r * p * r * p * q * r * p * r 
 20 p * q * r * p * q * r * p * q * r * p * q * r * p * q * r * p * q * r * p * r 
 20 p * q * r * p * r * p * q * r * p * q * r * p * r * p * q * r * p * r * p * r