A 1 3 the first term is 3 a n a n 1 2 add 2 to the previous term. Calculate f9 for the recursive series fx 3. We hit the seed value so we are done with the first phase.
Begin casesa 1 3leftarrowgray text the first term is 3 a n a n-12leftarrowgray text add 2 to the previous term end cases.
In other words through recursive formula we find the next terms of the sequence one by one. A 1 3 the first term is 3 a n a n 1 2 add 2 to the previous term. A1 1 a2 1 an an1 an2forn 3 a 1 1 a 2 1 a n a n 1 a n 2 for n 3. The first part tells us the first term of the sequence.