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   Problem Statement  

 Problem Statement for PreprimeNumbers

Problem Statement

    A number is preprime if it has exactly 4 positive integer divisors. For example, 6 is preprime because its divisors are 1, 2, 3, and 6. The integers 6, 8, 10, 14 form the beginning of an infinite sequence of preprime numbers. Find the n-th element of this sequence, where n is a 1-based index.
 

Definition

    
Class:PreprimeNumbers
Method:nthNumber
Parameters:int
Returns:int
Method signature:int nthNumber(int n)
(be sure your method is public)
    
 

Constraints

-n will be between 1 and 1000000, inclusive.
 

Examples

0)
    
2
Returns: 8
The beginning of an infinite sequence of preprime numbers is: 6, 8, 10, 14, ... The second number is 8.
1)
    
4
Returns: 14
The beginning of an infinite sequence of preprime numbers is: 6, 8, 10, 14, ... The fourth number is 14.
2)
    
24
Returns: 77
3)
    
43765
Returns: 193539

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This problem was used for:
       Single Round Match 307 Round 1 - Division II, Level Three