fn fprod(&mut self, n: usize) -> usize {
        *self.factor_cache.entry(n).or_insert(
            self.sieve.factor(n).unwrap().into_iter()
                      .fold(0, |sum, (p, _)| sum + p)
        )
    }
/// Return the product of distinct prime factors of `n`.
Return the product of distinct prime factors of `n`.
Return the product of distinct prime factors of ` n ` .
fn fprod(&mut self, n: usize) -> usize {
        *self.factor_cache.entry(n).or_insert(
            self.sieve.factor(n).unwrap().into_iter()
                      .fold(0, |sum, (p, _)| sum + p)
        )
    }
fn fprod ( & mut self , n : usize ) -> usize { * self . factor_cache . entry ( n ) . or_insert ( self . sieve . factor ( n ) . unwrap ( ) . into_iter ( ) . fold ( 0 , | sum , ( p , _ ) | sum + p ) ) }
Return the product of distinct prime factors of `n`.
Return the product of distinct prime factors of ` n ` .
&mut self
n
usize