refactor/clean a bit

src/is_prime.rs

@@ -7,7 +7,7 @@ pub mod prime_utils {
     }
 
     #[must_use]
-    pub fn is_prime(number: &BigUint, g_primes: &Vec<BigUint>) -> bool {
+    pub fn is_prime(number: &BigUint, g_primes: &[BigUint]) -> bool {
         if BigUint::from(1u8) == *number {
             return false;
         }
@@ -27,8 +27,8 @@ pub mod prime_utils {
 
             let sqrtnum = number.sqrt() + &one; //fake ceil function
 
-            for prime in g_primes {
-                if prime < &sqrtnum && number % prime == ZERO {
+            for prime in g_primes.iter().filter(|p| p < &&sqrtnum) {
+                if number % prime == ZERO {
                     return false;
                 }
             }

src/main.rs

@@ -23,7 +23,7 @@ fn p(n: f64) -> f64 {
     let ln_ln_ln_n = ln_ln_n.ln();
 
     n * (ln_n + ln_ln_n - 1.0 + (ln_ln_ln_n - 2.0) / ln_n
-        - ((ln_ln_n).powi(2) - 6.0 * ln_ln_n + 11.0) / (2.0 * 2.0f64.log2() * ln_n)
+        - ((ln_ln_n).powi(2) - 6.0 * ln_ln_n + 11.0) / (2.0 * ln_n)
         + ((ln_ln_n / ln_n).powi(3)) * (1.0 / ln_n))
 }