What is the correct supply voltage for LEDs?
Each red LED drops about 1.5V.  So three of them takes 4.5V, leaving only 0.5V for the resistors.
0.5 / (47+47+47) = 0.0035A or 3.5mA.  That's rather low.
If you were to remove two of the 47 ohm resistors, you would get
0.5 / 47 = 0.011A or 11mA.  That's brighter, but still less than most LEDs can handle.