int ledPins[] = {2, 4, 5, 6, 7, 13};
int numLeds = 6; 
void setup() {
  for (int i = 0; i < numLeds; i++) {
    pinMode(ledPins[i], OUTPUT);
  }
}

void loop() {
  
  for (int i = 0; i < numLeds; i++)
   {
    digitalWrite(ledPins[i], HIGH); 
    delay(500); 
    digitalWrite(ledPins[i], LOW); 
  }
  
  
}