Powering Multiple LEDS

Hi, Im very new to arduinos

I am wondering is it possible to wire say 15 leds in series then have them connect back to the arduino as you would with just one led?

asuming that each LED draws 20mA 15 would draw 300 mA. One Arduino pin can only supply 40mA. So you can not drive 15 LED's from one pin directly.

Look around this site for examples of driving LED's via a transistor and with an external powersupply. It's rather easy.

In series it would be more along the lines of each LED dropping about 2 volts, so 15 LEDs dropping about 30 volts at 20mA. Still well beyond what the Arduino can handle.