const uint8_t ledCount = 8;
const uint8_t ledRed = 13;

uint8_t ledPins[] = 
{
  0, 1, 2, 3, 4, 5, 6, 7
};  


void setup() 
{
  pinMode(ledRed, OUTPUT);
  for (uint8_t thisLed = 0; thisLed < ledCount; thisLed++) 
  {
    pinMode(ledPins[thisLed], OUTPUT);
  }
}

void loop() 
{
  for (uint8_t thisLed = 0; thisLed < ledCount; thisLed++) 
  {
    digitalWrite(ledPins[thisLed], HIGH);
    digitalWrite(ledRed, HIGH);
    delay(500);
    digitalWrite(ledPins[thisLed], LOW);
    digitalWrite(ledRed, LOW);
    delay(500);
  }
}