int LED = 2;
int btn = 11;

void setup() {
  pinMode(LED, OUTPUT);
  pinMode(btn, INPUT_PULLUP);
  digitalWrite(LED, LOW);
}

void loop() {
  if (digitalRead(btn) == LOW) {
    digitalWrite(LED, HIGH);
    delay(2500);
    digitalWrite(LED, LOW);
    delay(400);
    digitalWrite(LED, HIGH);
    delay(2500);
    digitalWrite(LED, LOW);
    delay(250);
    digitalWrite(LED, HIGH);
    delay(8000);
    digitalWrite(LED, LOW);
    delay(250);
    digitalWrite(LED, HIGH);
    delay(8000);
  }
}