While westfw's circuit is good, if you are making R1 equal to only one ohm then you are in effect relying on the voltage drop on each diode being 2 volts.
Using so many LEDs in series with a voltage that close to the limit is not a good idea. There is no head room for any voltage variations in the LEDs.
Also just like Christmas tree lights if one goes short you will over current the others and blow them too.
Much better to have five in series and use a 100R resistor. That will give you 10 volts across the LEDs and allow 20mA to flow.