254 Mr Hardy and Mr Littleiuood, Note etc. 



Similarly, suppose N(n) to be the number of pairs of solutions 

 of the equation 



a})' — hp = h 



such that p' < n. It is supposed that a and h have no common 

 factor. Then 



N(n) = o 



l(logw)- 



unless k is prime to both a and b, and one of the three is even. 

 If these conditions are satisfied 



where p is now an odd prime factor of k, a, or h. 



