No of strings of fixed length possible with a given grammar

Question

What is the number of terminal string of length <= 6 generated by the CFG shown below?
S -> 0A1
A -> BB1/B
B ->A/0/1

Do you have any semantic method to solve such questions based on some pattern that can generalizes up to any length string n ??

 

For the present question it is 6,quite simple to derive but  I am wondering what if it had been asked no of strings of length n

 

 

Thanks

Answer 1

You can use this kind of approach. Although it may look complicated but it totally depends on the grammar provided.