Project Euler 263(unsolved)

/**
 * Copyright uwi ( http://wonderfl.net/user/uwi )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/1haL
 */

package {
    import flash.display.Sprite;
    import flash.text.TextField;
    import flash.utils.getTimer;
    // @see http://projecteuler.net/index.php?section=problems&id=263
    public class Euler263 extends Sprite {
        private var _tf : TextField;
  
        public function Euler263() {
            _tf = new TextField();
            _tf.width = 465;
            _tf.height = 465;
            addChild(_tf);
            
            var s : int = getTimer();
            tr(solve());
            var g : int = getTimer();
            tr((g - s) + " ms");
        }

        private function solve() : Number
        {
        		var primes : Array = sieveEratosthenes(10000000);
        		var ct : uint = 0;
        		for(var i : uint = 0;i < primes.length - 3;i++){
        			if(
        				primes[i+1] - primes[i] == 6 &&
        				primes[i+2] - primes[i+1] == 6 && 
        				primes[i+3] - primes[i+2] == 6
        				){
//        					tr(primes[i], primes[i+1], primes[i+2], primes[i+3], i);
        					ct++;
        				}
        		}
        		tr(ct);
        		return 0;
        }

        private function sieveEratosthenes(n : int) : Array
        {
            var nn : uint = ((n / 2 - 1) >>> 5) + 1;
            var ar : Vector.<uint> = new Vector.<uint>(nn);
            var i : uint, j : uint;
            for(i = 0;i < nn - 1;i++)ar[i] = 0xffffffff;
            ar[nn - 1] = (1 << ((n / 2 - 1) & 31)) - 1;
            
            var sq : uint = (Math.sqrt(n) - 3) >>> 1;
            for(var p : uint = 0;p <= sq;p++){
                if(ar[p >>> 5] & (1 << (p & 31))){
                    var m : uint = (p << 1) + 3;
                    var m2 : uint = m << 1;
                    for(var mm : uint = m * m;mm <= n;mm += m2){
                        var ind : uint = (mm - 3) >>> 1;
                        ar[ind >>> 5] &= ~(1 << (ind & 31));
                    }
                }
            }
            
            var ret : Array = [2];
            for(i = 0;i < nn;i++){
                for(j = 0;j <= 31;j++){
                    if(ar[i] & (1 << j))ret.push((((i << 5) | j) << 1) + 3);
                }
            }
            return ret;
        }
        
        private function tr(...o : Array) : void
        {
            _tf.appendText(o + "\n");
            _tf.scrollV = _tf.maxScrollV;
        }
    }
}