int leds[4] = {4,5,6,7};
void setup() {
  // put your setup code here, to run once:
  for(int i=4; i<8; i++){
    pinMode(i, OUTPUT);
  }
}

void loop() {
  // put your main code here, to run repeatedly:
  for(int j=4; j<8; j++){
    digitalWrite(j, HIGH);
    delay(500);
    digitalWrite(j, LOW);
    //delay(300);
  }
}