Data update

Task/Digital-root-Multiplicative-digital-root/JavaScript/digital-root-multiplicative-digital-root.js

@@ -0,0 +1,31 @@
+function digmul(n) {
+  return [...String(n)].reduce((x, y) => Number(x) * Number(y));
+}
+
+function mdr_mp(n) {
+  let m = n, i = 0;
+  while (m > 9) {
+    m = digmul(m);
+    i++;
+  }
+  return {"MDR": m, "MP": i};
+}
+
+for (const n of [123321, 7739, 893, 899998]) {
+  console.log(`${n} has MDR ${mdr_mp(n)["MDR"]} and MP ${mdr_mp(n)["MP"]}`);
+}
+
+function first5mdr(n) {
+  let m = 0, nums = [];
+  while (nums.length < 5) {
+    if (mdr_mp(m)["MDR"] == n) {
+      nums.push(m);
+    }
+    m++;
+  }
+  return `First 5 numbers with MDR ${n}: ${nums.join(", ")}`;
+}
+
+for (let i = 0; i < 10; i++) {
+  console.log(first5mdr(i));
+}