int ledPin = 17;    
void setup() 
{  //pinMode(ledPin, OUTPUT);
}
void loop()
 {
for (int fadeValue = 0 ; fadeValue <= 255;  fadeValue += 5) 
{
analogWrite(ledPin, fadeValue);
delay(30);
  }
for (int fadeValue = 255 ; fadeValue >= 0; fadeValue -= 5) {
analogWrite(ledPin, fadeValue);
delay(100);
  }
}