Strange unique prime triplets: Difference between revisions

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 Found 241,580 strange prime triplets with n, m, p < 1,000.
+</pre>
+=={{header|Wren}}==
+{{trans|Wren}}
+<lang ecmascript>package main
+import "fmt"
+func isPrime(n int) bool {
+    switch {
+    case n < 2:
+        return false
+    case n%2 == 0:
+        return n == 2
+    case n%3 == 0:
+        return n == 3
+    default:
+        d := 5
+        for d*d <= n {
+            if n%d == 0 {
+                return false
+            }
+            d += 2
+            if n%d == 0 {
+                return false
+            }
+            d += 4
+        }
+        return true
+    }
+}
+func commatize(n int) string {
+    s := fmt.Sprintf("%d", n)
+    if n < 0 {
+        s = s[1:]
+    }
+    le := len(s)
+    for i := le - 3; i >= 1; i -= 3 {
+        s = s[0:i] + "," + s[i:]
+    }
+    if n >= 0 {
+        return s
+    }
+    return "-" + s
+}
+func strangePrimes(n int, countOnly bool) int {
+    c := 0
+    f := "%2d: %2d + %2d + %2d = %2d\n"
+    var s int
+    for i := 3; i <= n-4; i += 2 {
+        if isPrime(i) {
+            for j := i + 2; j <= n-2; j += 2 {
+                if isPrime(j) {
+                    for k := j + 2; k <= n; k += 2 {
+                        if isPrime(k) {
+                            s = i + j + k
+                            if isPrime(s) {
+                                c++
+                                if !countOnly {
+                                    fmt.Printf(f, c, i, j, k, s)
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+    return c
+}
+func main() {
+    fmt.Println("Unique prime triples under 30 which sum to a prime:")
+    strangePrimes(29, false)
+    cs := commatize(strangePrimes(999, true))
+    fmt.Printf("\nThere are %s unique prime triples under 1,000 which sum to a prime.\n", cs)
+}</lang>
+{{out}}
+<pre>
+Unique prime triples under 30 which sum to a prime:
+:  3 +  5 + 11 = 19
+:  3 +  5 + 23 = 31
+:  3 +  5 + 29 = 37
+:  3 +  7 + 13 = 23
+:  3 +  7 + 19 = 29
+:  3 + 11 + 17 = 31
+:  3 + 11 + 23 = 37
+:  3 + 11 + 29 = 43
+:  3 + 17 + 23 = 43
+:  5 +  7 + 11 = 23
+:  5 +  7 + 17 = 29
+:  5 +  7 + 19 = 31
+:  5 +  7 + 29 = 41
+:  5 + 11 + 13 = 29
+:  5 + 13 + 19 = 37
+:  5 + 13 + 23 = 41
+:  5 + 13 + 29 = 47
+:  5 + 17 + 19 = 41
+:  5 + 19 + 23 = 47
+:  5 + 19 + 29 = 53
+:  7 + 11 + 13 = 31
+:  7 + 11 + 19 = 37
+:  7 + 11 + 23 = 41
+:  7 + 11 + 29 = 47
+:  7 + 13 + 17 = 37
+:  7 + 13 + 23 = 43
+:  7 + 17 + 19 = 43
+:  7 + 17 + 23 = 47
+:  7 + 17 + 29 = 53
+:  7 + 23 + 29 = 59
+: 11 + 13 + 17 = 41
+: 11 + 13 + 19 = 43
+: 11 + 13 + 23 = 47
+: 11 + 13 + 29 = 53
+: 11 + 17 + 19 = 47
+: 11 + 19 + 23 = 53
+: 11 + 19 + 29 = 59
+: 13 + 17 + 23 = 53
+: 13 + 17 + 29 = 59
+: 13 + 19 + 29 = 61
+: 17 + 19 + 23 = 59
+: 19 + 23 + 29 = 71
+There are 241,580 unique prime triples under 1,000 which sum to a prime.
 </pre>