const int leds= 9;

int led_pin[]{
  1, 2, 3, 4, 5, 6, 7, 8
};

void setup() {
  for(int this_loop = leds; this_loop >= 0; this_loop--){
    pinMode(led_pin[this_loop], OUTPUT);
    digitalWrite(led_pin[this_loop], LOW);
    delay(500);
  }
}

void loop() {
  for(int this_loop; this_loop < leds; this_loop++){
    digitalWrite(led_pin[this_loop], HIGH);
    delay(1000);
  }
}