There are many possibilities, as your question is not stating the set of n's on which a_n is calculated. Sounds like a high school question which typical means n=1 is the first term. What answer do you get for this value?
There are many possibilities, as your question is not stating the set of n's on which a_n is calculated. Sounds like a high school question which typical means n=1 is the first term. What answer do you get for this value?