1 files changed, 94 insertions, 0 deletions
diff --git a/challenge-159/roger-bell-west/javascript/ch-2.js b/challenge-159/roger-bell-west/javascript/ch-2.js
new file mode 100755
index 0000000000..619b239213
--- /dev/null
+++ b/challenge-159/roger-bell-west/javascript/ch-2.js
@@ -0,0 +1,94 @@
+#! /usr/bin/node
+
+function genprimes(mx) {
+    let primesh=new Set([2,3])
+    for (let i = 6; i <= mx; i += 6) {
+        for (let j = i-1; j <= i+1; j += 2) {
+            if (j <= mx) {
+                primesh.add(j);
+            }
+        }
+    }
+    let q=[2,3,5,7];
+    let p=q.shift();
+    let mr=Math.floor(Math.sqrt(mx));
+    while (p <= mr) {
+        if (primesh.has(p)) {
+            let i=p*p
+            for (let i=p*p; i <= mx; i += p) {
+                primesh.delete(i);
+            }
+        }
+        if (q.length < 2) {
+            q.push(q[q.length-1]+4);
+            q.push(q[q.length-1]+2);
+        }
+        p=q.shift();
+    }
+    let primes=[...primesh];
+    primes.sort(function(a,b) {
+        return a-b;
+    });
+    return primes;
+}
+
+function primefactor (n) {
+    let f=new Map()
+    let m=n
+    for (let p of genprimes(Math.floor(Math.sqrt(n)))) {
+        while (m % p == 0) {
+            m=Math.floor(m/p)
+            if (f.has(p)) {
+                f.set(p,f.get(p)+1)
+            } else {
+                f.set(p,1)
+            }
+            if (m == 1) {
+                break
+            }
+        }
+    }
+    if (m > 1) {
+        if (f.has(m)) {
+            f.set(m,f.get(m)+1)
+        } else {
+            f.set(m,1)
+        }
+    }
+    return f
+}
+
+function moebius (n) {
+    let z=0
+    for (let v of primefactor(n).values()) {
+        if (v > 1) {
+            return 0
+        }
+        z++
+    }
+    if (z % 2 == 0) {
+        return 1
+    }
+    return -1
+}
+
+if (moebius(5) == -1) {
+    process.stdout.write("Pass");
+} else {
+    process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+
+if (moebius(10) == 1) {
+    process.stdout.write("Pass");
+} else {
+    process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+
+if (moebius(20) == 0) {
+    process.stdout.write("Pass");
+} else {
+    process.stdout.write("FAIL");
+}
+process.stdout.write("\n");