int buzzer=7;
int LED=13;

void setup() {
  pinMode(buzzer, OUTPUT);
  pinMode(LED, OUTPUT);
}

void loop() {
  tone(buzzer, 523);
  digitalWrite(LED, HIGH);
  delay(300);
  digitalWrite(LED, LOW);
  delay(300);
  tone(buzzer, 400);
  digitalWrite(LED, HIGH);
  delay(300);
  digitalWrite(LED, LOW);
  delay(300);
}