Nov 30, 2022 · Nov 27, 2022 · Nov 27, 2022 · Nov 27, 2022
diff --git a/Maths/FriendlyNumbers.js b/Maths/FriendlyNumbers.js
 /*
  'In number theory, friendly numbers are two or more natural numbers with a common abundancy index, the
  ratio between the sum of divisors of a number and the number itself.'
  Source: https://en.wikipedia.org/wiki/Friendly_number
  See also: https://mathworld.wolfram.com/FriendlyNumber.html#:~:text=The%20numbers%20known%20to%20be,numbers%20have%20a%20positive%20density.
 */

 export const FriendlyNumbers = (firstNumber, secondNumber) => {
  // input: two integers
  // output: true if the two integers are friendly numbers, false if they are not friendly numbers

  // First, check that the parameters are valid
  if (!Number.isInteger(firstNumber) || !Number.isInteger(secondNumber) || firstNumber === 0 || secondNumber === 0 || firstNumber === secondNumber) {
    throw new Error('The two parameters must be distinct, non-null integers')
  }

  return abundancyIndex(firstNumber) === abundancyIndex(secondNumber)
 }

 function abundancyIndex (number) {
  return sumDivisors(number) / number
 }

 function sumDivisors (number) {
  let runningSumDivisors = number
  for (let i = 0; i < number / 2; i++) {
    if (Number.isInteger(number / i)) {
      runningSumDivisors += i
    }
  }
  return runningSumDivisors
 }
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,32 @@
		/*
		'In number theory, friendly numbers are two or more natural numbers with a common abundancy index, the
		ratio between the sum of divisors of a number and the number itself.'
		Source: https://en.wikipedia.org/wiki/Friendly_number
		See also: https://mathworld.wolfram.com/FriendlyNumber.html#:~:text=The%20numbers%20known%20to%20be,numbers%20have%20a%20positive%20density.
		*/

		export const FriendlyNumbers = (firstNumber, secondNumber) => {
		// input: two integers
		// output: true if the two integers are friendly numbers, false if they are not friendly numbers

		// First, check that the parameters are valid
		if (!Number.isInteger(firstNumber) \|\| !Number.isInteger(secondNumber) \|\| firstNumber === 0 \|\| secondNumber === 0 \|\| firstNumber === secondNumber) {
		throw new Error('The two parameters must be distinct, non-null integers')
		}

		return abundancyIndex(firstNumber) === abundancyIndex(secondNumber)
		}

		function abundancyIndex (number) {
		return sumDivisors(number) / number
		}

		function sumDivisors (number) {
		let runningSumDivisors = number
		for (let i = 0; i < number / 2; i++) {
		if (Number.isInteger(number / i)) {
		runningSumDivisors += i
		}
		}
		return runningSumDivisors
		}