Add Pascal's triangle.

src/algorithms/math/pascal-triangle/pascalTriangleRecursive.js

@@ -0,0 +1,30 @@
+/**
+ * @param {number} lineNumber
+ * @return {number[]}
+ */
+export default function pascalTriangleRecursive(lineNumber) {
+  if (lineNumber === 0) {
+    return [1];
+  }
+
+  const currentLineSize = lineNumber + 1;
+  const previousLineSize = currentLineSize - 1;
+
+  // Create container for current line values.
+  const currentLine = [];
+
+  // We'll calculate current line based on previous one.
+  const previousLine = pascalTriangleRecursive(lineNumber - 1);
+
+  // Let's go through all elements of current line except the first and
+  // last one (since they were and will be filled with 1's) and calculate
+  // current coefficient based on previous line.
+  for (let numIndex = 0; numIndex < currentLineSize; numIndex += 1) {
+    const leftCoefficient = (numIndex - 1) >= 0 ? previousLine[numIndex - 1] : 0;
+    const rightCoefficient = numIndex < previousLineSize ? previousLine[numIndex] : 0;
+
+    currentLine[numIndex] = leftCoefficient + rightCoefficient;
+  }
+
+  return currentLine;
+}