The skecth is made with Arduino 1.6.7

/*
LED Brightness
Turns on an LED on for one second, 4 with different resistors so the LED brightess will change.

This example code is in the public domain.

modified 28 feb 2016
by www.avrprojects.net
*/

// the setup function runs once when you press reset or power the board
void setup()
{
for(int a=0;a<13;) pinMode(a++,OUTPUT); // set all pins to output
}

// the loop function runs over and over again forever
void loop()
{
digitalWrite(2, HIGH); // turn the LED on (HIGH is the voltage level)
delay(500); // wait ms
digitalWrite(2, LOW); // turn the LED off by making the voltage LOW
digitalWrite(3, HIGH); // turn the LED on (HIGH is the voltage level)
delay(500); // wait ms
digitalWrite(3, LOW); // turn the LED off by making the voltage LOW
digitalWrite(4, HIGH); // turn the LED on (HIGH is the voltage level)
delay(500); // wait ms
digitalWrite(4, LOW); // turn the LED off by making the voltage LOW
digitalWrite(5, HIGH); // turn the LED on (HIGH is the voltage level)
delay(500); // wait ms
digitalWrite(5, LOW); // turn the LED off by making the voltage LOW
}