Here is a sequence of numbers:

1 11 21 1211 111221

It seems to be a strange sequence, but there is a system behind it...

The question: What is the next number in this sequence?

The solution: Click here!

Another question: Here is another sequence of numbers:

1 11 21 1211 1231 131221

What is the next number in this sequence?

Another solution: Click here!

Yet another question: Here is another sequence of numbers:

0 10 1110 3110 132110 1113122110

What is the next number in this sequence?

Yet another solution: Click here!