Multiplicatively perfect numbers: Difference between revisions

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@@ Line 222: / Line 222: @@
 =={{header|Go}}==
 {{trans|C}}
+{{libheader|Go-rcu}}
+Run time around 9.2 seconds.
 <syntaxhighlight lang="go">package main
@@ Line 228: / Line 230: @@
     "rcu"
 )
+// library method customized for this task
+func Divisors(n int) []int {
+    var divisors []int
+    i := 1
+    k := 1
+    if n%2 == 1 {
+        k = 2
+    }
+    for ; i*i <= n; i += k {
+        if i > 1 && n%i == 0 { // exclude 1 and n
+            divisors = append(divisors, i)
+            if len(divisors) > 2 { // not eligible if has > 2 divisors
+                break
+            }
+            j := n / i
+            if j != i {
+                divisors = append(divisors, j)
+            }
+        }
+    }
+    return divisors
+}
 func main() {
@@ Line 240: / Line 265: @@
     for i := 0; ; i++ {
         if i != 1 {
-            divs = rcu.ProperDivisors(i)
+            divs = Divisors(i)
         } else {
             divs = []int{1, 1}
         }
-        length := len(divs)
+        if len(divs) == 2 && divs[0]*divs[1] == i {
-        if length > 1 {
+            count++
-            prod := 1
+            if i < 500 {
-            for d := 1; d < length; d++ {
+                fmt.Printf("%3d  ", i)
-                prod *= divs[d]
+                if count%10 == 0 {
-            }
+                    fmt.Println()
-            if prod == i {
-                count++
-                if i < 500 {
-                    fmt.Printf("%3d  ", i)
-                    if count%10 == 0 {
-                        fmt.Println()
-                    }
                 }
             }
@@ Line 279: / Line 297: @@
             scount := rcu.Commatize(count)
             st := rcu.Commatize(t)
-            fmt.Printf("Counts under %7s: MPNs = %7s  Semi-primes = %7s\n", slimit, scount, st)
+            fmt.Printf("Counts under %9s: MPNs = %7s  Semi-primes = %7s\n", slimit, scount, st)
-            if limit == 500000 {
+            if limit == 5000000 {
                 break
             }