Astable Multivibrator 3.3v

You just need to either shake your phone and maybe make the time quicker. Shaking your phone starts oscillation

Consider 62 Ohm led resistors.

CN you tell me a bit more about why 62 ohms is the way to go?

Sorry for taking so long to answer, I didn't realize that you had re-posted. The transistor has a gain of 100, ie in a properly biased circuit, for every 1 unit of base current the collector current can be 100 times higher, when the collector current reaches its limiting current (as defined collectors load) the input/output ratio gets higher than 1 to 100, the base current ratio then being too high will saturate the base and tend to lock it on (thus making it difficult to use as an oscillator). This can be remedied in one of two ways just by bringing the input/output ratio under 1 to 100 , 1. increase the base resistor to lower the base current, or 2. decreasing the collector resistor to increase the collector current. In this circuit, as the led current needed adjusting to get it closer to 20 mA, adjusting the collector resistor was the way to go. Most times in oscillator circuits, it is best to adjust the collector output current to just over the amount desired, then slightly increase the base resistor to ensure that the base is sensitive.