Added Aliquot Sum Implementation

Maths/AliquotSum.js

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+/*
+  A program to calculate the Aliquot Sum of a number.
+  The aliquot sum of a number n, is the sum of all the proper divisors of n apart from n itself
+  For example, for the number 6
+  The divisors are 1, 2, 3 (we don't consider 6), so its aliquot sum is 1 + 2 + 3 = 6
+  1 is the only number whose aliquot sum is 0 (since its only divisor is 1 and aliquot sum of a number couldn't have itself)
+  For all prime numbers, the aliquot sum is 1, since their only divisor apart from themselves is 1
+  Article on Aliquot Sum: https://en.wikipedia.org/wiki/Aliquot_sum
+ */
+
+/**
+ * @param {Number} input The number whose aliquot sum you want to calculate
+ */
+function aliquotSum (input) {
+  // input can't be negative
+  if (input < 0) throw new TypeError('Input cannot be Negative')
+
+  // input can't be a decimal
+  if (Math.floor(input) !== input) throw new TypeError('Input cannot be a Decimal')
+
+  // Dealing with 1, which isn't a prime
+  if (input === 1) return 0
+
+  let sum = 0
+  for (let i = 1; i <= (input / 2); i++) {
+    if (input % i === 0) sum += i
+  }
+
+  return sum
+}
+
+export { aliquotSum }

Maths/test/AliquotSum.test.js

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+import { aliquotSum } from '../AliquotSum'
+
+describe('Aliquot Sum of a Number', () => {
+  it('Aliquot Sum of 6', () => {
+    expect(aliquotSum(6)).toBe(6)
+  })
+
+  it('Aliquot Sum of 1', () => {
+    expect(aliquotSum(1)).toBe(0)
+  })
+
+  it('Aliquot Sum of 28', () => {
+    expect(aliquotSum(28)).toBe(28)
+  })
+})