Calculating Iadj for voltage regulator
It's in the datasheet-- use the typical number (50uA). Usually it will make little difference compared to resistor tolerances, especially if you're counting on the resistors to draw the minimum load current.

As others have mentioned, there isn't enough voltage for a LM317. Try a LM1117/AMS1117 (quasi-LDO) or better, and be sure to carefully follow the recommendations for the output capacitor on any LDO regulator.