#define LED_PIN_1 11
#define LED_PIN_2 10
#define LED_PIN_3 9
#define LED_PIN_4 8
#define LED_PIN_5 7
#define LED_PIN_6 6

unsigned long previousMillis[6]; //[x] = number of leds

void setup() { 
  pinMode(LED_PIN_1, OUTPUT);   
  pinMode(LED_PIN_2, OUTPUT);  
  pinMode(LED_PIN_3, OUTPUT);  
  pinMode(LED_PIN_4, OUTPUT);
  pinMode(LED_PIN_5, OUTPUT);
  pinMode(LED_PIN_6, OUTPUT);


}
void loop() {
 BlinkLed(LED_PIN_1, 3000, 0);   //BlinkLed( which led, interval, one of the stored prevMillis
 BlinkLed(LED_PIN_2, 3000, 1);  //last parameters must be different for each led
 BlinkLed(LED_PIN_3, 3000, 2);
 BlinkLed(LED_PIN_4, 1500, 3);
 BlinkLed(LED_PIN_5, 4000, 4);
 BlinkLed(LED_PIN_6, 2000, 5);

}

void BlinkLed (int led, int interval, int array){   
  
  //(long) can be omitted if you dont plan to blink led for very long time I think
   if (((long)millis() - previousMillis[array]) >= interval){ 
   
    previousMillis[array]= millis(); //stores the millis value in the selected array
   
    digitalWrite(led, !digitalRead(led)); //changes led state
  }
 }
// Written by FabrizioP @ Instructables.com</p>