console.log("With 500");
console.log(randomNumber(500));
console.log("With 1");
console.log(randomNumber(1));
console.log("With 500");
console.log(randomNumber(500));
console.log("With 1000001");
console.log(randomNumber(1000001));

/*

Some tests

With 500
19
With 1
1
With 500
31
With 1000001
Number bigger than expected.
undefined

With 500
169
With 1
0
With 500
273
With 1000001
Number bigger than expected.
undefined

*/

function flip() {
  return Math.random() >= 0.5;
}

/**
 * This function uses a modified version of the Middle Square Weyl Sequence PRNG algorithm
 *
 * @param {*} max Max number in the iterval
 * @param {*} min Min number in the interval (for this test will be always 0)
 */
function msws(max, min) {
  var clamped = !!max; // returns a Boolean value (true or false) depending on the truthiness of the expression.
  var done = false;
  var i = 0;
  var x = 0;
  var w = 0;
  var j = 0;
  // To give it a feeling of more randomness I'm adding these few lines with the use of flip()
  var primes = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97];
  // First select a seed based on the result of flip
  if(flip()){
    s = 0x45ad4e1ce2ace;
  } else {
    s = 0x165ad49659;
  }
  // Add these three call to flip() to have more randomness in the seed, in each iteration the seed will change using the first 25
  // numbers
  while(flip() && flip() || flip()){
    s *= primes[j];
    j++;
    if(j === 5){
      j = 0;
    }
  }
  if(max > 1000000 || max < 0){
    console.log("Number bigger than expected.");
    return;
  }
  while (!done) {
    i += 1;
    x *= x;
    x += (w += s);
    x = (x >> 16) | (x << 16);
    x = (x < 0) ? x * -1 : x;
    var outOfBounds = clamped && ((x > max) || (min && x < min));
    if (!clamped) {
      done = true;
    } else if (!outOfBounds) {
      done = true;
    }
  }
  return x;
}

function randomNumber(max) {
  return msws(max, 0);
}