I was thinking of using one of these:

http://www.mouser.com/ds/1/311/RTB_GFTM_Pb_free-24628.pdfin a project and I am a bit confused on the correct value resistor to use. I am powering my project from a 3.7V LiPo battery and a 3.3V regulator. Page 4 of the PDF linked above shows a forward voltage for the green LED of 3.2V and a forward current of 20mA. I believe the formula to use would be (3.3 - 3.2)/.02A which would equal a resistor value of 5 Ohms. This seems really small and I would like to verify that this is correct. Any assistance would be great! Thanks!