Series was like this 1,11,21,1211,111221,.. Find next term in sequence????

You have to speak each term.

Ex: First term is 1. Speak it as one 1 i.e. 11
Then speak 11 as two 1 i.e. 21
Now speak this as one 2 one 1 i.e. 1211
next terms will be 111221, 312211, 13112221