Problem 55595. Easy Sequences 87: Perfect Power Modular Residue of a Nested Sum-product Function
For a positive integer x, we define the function Y, as follows:
Hence, for 
 we have:
And if  
:
-----------------------------
We now consider the following congruence:
The congruence expresses the possibility that the nested sum and product function defined above (Y), can have a perfect power residue in some modular base. In fact, solving for x, the congruence always have a trivial solution, namely 
, that's because 
, which is, of course, a perfect power in any modular base. 
Given the value of integers N, M, and certain limit L, find the sum S of all positive integer values of 
, that satisfies the above congruence.
For 
, 
 and 
, we see that only 
and 
 satisfies the congruence, since: 
Therefore in this case S(20,7,3) = 1 + 5 = 6.
For 
, 
 and 
, the above equation is satisfied, 
.
Therefore: S(20,10,3) = sum(1:20) = 210.
Solution Stats
Problem Comments
- 
		2 Comments
 
		David Hill
    	on 1 Jan 2023
	
	
  	I am getting all test solutions correct except: test2, test5, and test8.
For test2 for example, I am only getting [1 5] = 6.
		Ramon Villamangca
    	on 2 Jan 2023
	
	
  	Hi David, test suites has been corrected. Please try again. Thanks.
Solution Comments
Show commentsProblem Recent Solvers2
Suggested Problems
- 
         
Compute a dot product of two vectors x and y
1021 Solvers
 - 
         
         
1549 Solvers
 - 
         
convert matrix to single column
422 Solvers
 - 
         
Create a two dimensional zero matrix
510 Solvers
 - 
         
         
7734 Solvers
 
More from this Author116
Problem Tags
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!