Another update from ingydotnet^djgoku

Task/Amicable-pairs/JavaScript/amicable-pairs-1.js

@@ -0,0 +1,61 @@
+(function (max) {
+
+    // Proper divisors
+    function properDivisors(n) {
+        if (n < 2) return [];
+        else {
+            var rRoot = Math.sqrt(n),
+                intRoot = Math.floor(rRoot),
+
+                lows = range(1, intRoot).filter(function (x) {
+                    return (n % x) === 0;
+                });
+
+            return lows.concat(lows.slice(1).map(function (x) {
+                return n / x;
+            }).reverse().slice((rRoot === intRoot) | 0));
+        }
+    }
+
+    // [m..n]
+    function range(m, n) {
+        var a = Array(n - m + 1),
+            i = n + 1;
+        while (i--) a[i - 1] = i;
+        return a;
+    }
+
+    // Filter an array of proper divisor sums,
+    // reading the array index as a function of N (N-1)
+    // and the sum of proper divisors as a potential M
+
+    var pairs = range(1, max).map(function (x) {
+        return properDivisors(x).reduce(function (a, d) {
+            return a + d;
+        }, 0)
+    }).reduce(function (a, m, i, lst) {
+        var n = i + 1;
+
+        return (m > n) && lst[m - 1] === n ? a.concat([[n, m]]) : a;
+    }, []);
+
+    // [[a]] -> bool -> s -> s
+    function wikiTable(lstRows, blnHeaderRow, strStyle) {
+        return '{| class="wikitable" ' + (
+            strStyle ? 'style="' + strStyle + '"' : ''
+        ) + lstRows.map(function (lstRow, iRow) {
+            var strDelim = ((blnHeaderRow && !iRow) ? '!' : '|');
+
+            return '\n|-\n' + strDelim + ' ' + lstRow.map(function (v) {
+                return typeof v === 'undefined' ? ' ' : v;
+            }).join(' ' + strDelim + strDelim + ' ');
+        }).join('') + '\n|}';
+    }
+
+    return wikiTable(
+        [['N', 'M']].concat(pairs),
+        true,
+        'text-align:center'
+    ) + '\n\n' + JSON.stringify(pairs);
+
+})(20000);

Task/Amicable-pairs/JavaScript/amicable-pairs-2.js

@@ -0,0 +1,2 @@
+[[220,284],[1184,1210],[2620,2924],[5020,5564],
+ [6232,6368],[10744,10856],[12285,14595],[17296,18416]]