diff --git a/DIRECTORY.md b/DIRECTORY.md
index df10ce16c0..315810f062 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -142,6 +142,7 @@
   * [BinaryExponentiationRecursive](Maths/BinaryExponentiationRecursive.js)
   * [BisectionMethod](Maths/BisectionMethod.js)
   * [CheckKishnamurthyNumber](Maths/CheckKishnamurthyNumber.js)
+  * [CollatzSequence](Maths/CollatzSequence.js)
   * [Coordinate](Maths/Coordinate.js)
   * [CoPrimeCheck](Maths/CoPrimeCheck.js)
   * [DecimalExpansion](Maths/DecimalExpansion.js)
@@ -159,6 +160,7 @@
   * [FigurateNumber](Maths/FigurateNumber.js)
   * [FindHcf](Maths/FindHcf.js)
   * [FindLcm](Maths/FindLcm.js)
+  * [FindMaxRecursion](Maths/FindMaxRecursion.js)
   * [FindMin](Maths/FindMin.js)
   * [FindMinIterator](Maths/FindMinIterator.js)
   * [GetEuclidGCD](Maths/GetEuclidGCD.js)
@@ -166,6 +168,7 @@
   * [IsDivisible](Maths/IsDivisible.js)
   * [IsEven](Maths/IsEven.js)
   * [IsOdd](Maths/IsOdd.js)
+  * [IsPronic](Maths/IsPronic.js)
   * [LeapYear](Maths/LeapYear.js)
   * [LinearSieve](Maths/LinearSieve.js)
   * [LucasSeries](Maths/LucasSeries.js)
@@ -197,6 +200,7 @@
   * [SquareRoot](Maths/SquareRoot.js)
   * [SumOfDigits](Maths/SumOfDigits.js)
   * [SumOfGeometricProgression](Maths/SumOfGeometricProgression.js)
+  * [TwinPrime](Maths/TwinPrime.js)
   * [Volume](Maths/Volume.js)
   * [WhileLoopFactorial](Maths/WhileLoopFactorial.js)
   * [ZellersCongruenceAlgorithm](Maths/ZellersCongruenceAlgorithm.js)
diff --git a/Search/test/InterpolationSearch.test.js b/Search/test/InterpolationSearch.test.js
new file mode 100644
index 0000000000..744a74855b
--- /dev/null
+++ b/Search/test/InterpolationSearch.test.js
@@ -0,0 +1,15 @@
+import { interpolationSearch } from '../InterpolationSearch'
+
+test('interpolationSearch([2, 6, 8, 14, 122, 169], 144) => -1', () => {
+  const array = [2, 6, 8, 14, 122, 169]
+  const key = 144
+  const res = interpolationSearch(array, key)
+  expect(res).toEqual(-1)
+})
+
+test('interpolationSearch([2, 6, 8, 14, 122, 169], 122) => 4', () => {
+  const array = [2, 6, 8, 14, 122, 169]
+  const key = 122
+  const res = interpolationSearch(array, key)
+  expect(res).toEqual(4)
+})