int i;

void setup()
{
  for(i= 2; i<8; i=i+1 ){
    pinMode( i, OUTPUT);
  }
}

void loop(){
  for (i=2; i<8; i=i+1)
{
  digitalWrite(i, HIGH);
  delay(1000); // Wait for 1000 millisecond(s)
  digitalWrite(i, LOW);
  delay(1000); // Wait for 1000 millisecond(s)
  }
}