a *= b not equivalent to a = a*b

[mlzarathustra at gmail.com]

Precedence, d'oh!

        rs *= (n-(i-1))/i  
is equivalent to:
        rs = rs * ((n-(i-1))/i)

not
        rs = rs * (n-(i-1))/i 

which is the same as 
        rs = ( rs * (n-(i-1)) )  /i 


Ken Iverson was right. Precedence is a bad idea.