Prime SieveOfEratosthenes

// Javascript program to check Euclid Number
var MAX = 10000;
var arr = [];

// Function to generate prime numbers
function SieveOfEratosthenes()
{

    // Create a boolean array "prime[0..n]" and initialize
    // all entries it as true. A value in prime[i] will
    // finally be false if i is Not a prime, else true.
    var prime = Array(MAX).fill(true);;

    for (var p = 2; p * p < MAX; p++) {
        // If prime[p] is not changed, then it is a prime

        if (prime[p] == true) {

            // Update all multiples of p
            for (var i = p * 2; i < MAX; i += p)
                prime[i] = false;
        }
    }

    // store all prime numbers
    // to vector 'arr'
    for (var p = 2; p < MAX; p++)
        if (prime[p])
            arr.push(p);
}

// Function to check the number for Euclid Number
function isEuclid( n)
{

    var product = 1;
    var i = 0;

    while (product < n) {

        // Multiply next prime number
        // and check if product + 1 = n
        // holds or not
        product = product * arr[i];

        if (product + 1 == n)
            return true;

        i++;
    }

    return false;
}

// Driver code

// Get the prime numbers
debugger;
SieveOfEratosthenes();

// Get n
var n = 31;

// Check if n is Euclid Number
if (isEuclid(n))
    document.write("YES<br>");
else
    document.write("NO<br>");

// Get n
n = 42;

// Check if n is Euclid Number
if (isEuclid(n))
    document.write("YES<br>");
else
    document.write("NO<br>");