Those questions are most of the times "useless", meaning they don't have unique answers. Sometimes, you can see an obvious pattern (e.g. 2,4,8,16,32,...) which makes you think there is only one continuation (64,128). Sometimes there are more than one patterns (don't have an example right away - will think about one). From a mathematical point of view, any continuation is possible.
In your case, there isn't an obvious pattern. Maybe there is a hidden pattern (like modulo a certain prime, numbers for letters etc.), but it is not obvious. So any continuation is mathematically as good as the other.
Best Answer
After first 3 digits get sum or first 2 digits and add 3,4,5,6 For exampe (3+6)+3=12 (12+6)+4=22 (22+12)+5=39 (39+22)+6=67 (67+39)+7=113 and so on