#define PAUSE 250

void setup() {
  pinMode(13, OUTPUT);
}

void loop() {
  threeblink(13,PAUSE);
  threeblink(13,3*PAUSE);
  delay(500);
}

void threeblink(int led, int ms) {
  for (int i=0; i<3;)
  {
    delay(ms);
    digitalWrite(led, HIGH);
    delay(ms);
    digitalWrite(led,LOW);
    i++;
  }
}