Numerical calculation of Apéry's Constant

apéys_constant.swift

import Foundation

func gcd(_ m: Int, _ n: Int) -> Int {
	var a = 0
	var b = max(m, n)
	var r = min(m, n)
	
	while r != 0 {
		a = b
		b = r
		r = a % b
	}
	return b
}

let totalEntries: Int = 1_000_000
var totalCoprimes: Int = 0

for _ in 0..<totalEntries {
	let a: Int = Int(arc4random())
	let b: Int = Int(arc4random())
	let c: Int = Int(arc4random())

	let greatestCommonDivisor = gcd(a, gcd(b, c))
	if greatestCommonDivisor == 1 {
		totalCoprimes += 1
	}
}

print(Double(totalEntries) / Double(totalCoprimes))