int ledPins[] = {5, 6, 9, 10, 11, A7};

void setup() {
  for (int i = 0; i < 6; i++) {
    pinMode(ledPins[i], OUTPUT);
  }
}

void loop() {
  for (int i = 0; i < 6; i++) {
    digitalWrite(ledPins[i], HIGH);
    delay(400);
    digitalWrite(ledPins[i], LOW);
    delay(200);
  }
}