Resistors for transistor led circuit
You want to turn the transistor on in saturation, that means that you want to give it more base current that it need for the collector current. This will ensure that it has a low voltage drop across collector to emitter. When we have a volt of so across collector to emitter, the ratio of collector current to emitter current is given by the transistor's HFE. you transistor has a minimum HFE of 110. Let us use a ratio of one fifth that value 22. This will make sure that the transistor is fully on. One fifth of the collector current is 4mA. Let us assume you control this circuit with a 3.3V input. R2 will have a voltage drop of 3.3V - the base emitter voltage of the transistor. Assuming 0.7V for VBE, VR2 = 2.6V. R2 = 2.6 / 4mA = 650 ohms. Nearest E12 values are 680 or 560ohms. Either will do here.