How about this?....
byte ledPins[] = { 13, 12, 8, 7, 4, 2};
for (int x=0; x<6; x++) {
digitalWrite(ledPins[x], HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(ledPins[x], LOW); // turn the LED off by making the voltage LOW
delay(1000); // wait for a second
}