// https://projecteuler.net/problem=7 const num = 10001; let primes = [2,3,5,7,11,13]; const calculatePrime = (num) => { let count = primes.length; let current = primes[count-1] + 1; while (count < num) { // go through each prime and see if divisible by the previous primes let prime = false; primes.some((n, i) => { if (current % n !== 0) { if (i === count-1) { prime = true; } } else { return true; } }) if (prime) { primes.push(current); count += 1; } current += 1; } return primes[num-1]; } console.log(calculatePrime(num));