OK, this is an oldie but a goodie... 1, 11, 21, 1211, 111221, 312211, ??? For the moment, if you get it, why not just post the next few and let other people go mad? ;-)

13112221,1113213211,31131212131221,1321131112111213112211,..... okokok it goes like this

in each number, two digits are used to represent a particular digit or the same consecutive digit in the previous number. The first digit is the number of times it is been repeated and the second digit is the value of the digit.

For example : First number = 1 Second number = "one" 1 = 11 --> because there is one one Thrird number = 21 -->(beacause there is 2 ones ) Fourth number = 1211 -->(becaouse there is one 2 and one 1 ) continuing similarly... 111221, 312211, 13112221,1113213211,31131212131221,1321131112111213112211 ...