The series resistor is a 220 ohm 1/8 watt resistor. I did play with the values(to increase the base current/led brightness) but then lower you go obviously puts stress on the LED. I went down to 10 ohms and that helped a little but the resistor was heating up due to so much current. Yes I blew out a few LED's
I did see that part of the datasheet.
So,
With a 220 ohm series resistor on the "base". And with a Forward voltage drop of ~1.2V I get a current of:
V = IR
1.2 = I*220
I = 5.4mA