25 Aug
                
                    2015
                
            
            
                25 Aug
                
                '15
                
            
            
            
        
    
                10:46 p.m.
            
        On Mon, Aug 24, 2015 at 1:38 AM, William Yager 
See section 4.4. http://cacr.uwaterloo.ca/hac/about/chap4.pdf
If it helps to have a (small) prime number generator, there's an efficient implementation in exact-combinatorics[1] [1] http://hackage.haskell.org/package/exact-combinatorics -- Live well, ~wren