6,6,6 = 6*36 = T3   = all possible ways to fill first 3 locations
6,1,1 = 6*1  = B1,3 = ways to violate C1 (after filling 3 locations)
6,5,1 = 6*5  = B2,3 = ways to not violate C1 but might violate C2
      = 6*30 = B0,3 = ways to not violate C1 nor C2 (via subtraction)