5. [-/1 Points]
DETAILS
SCALCET8 11.1.501.XP.MI.
Find a formula for the general term $a_n$ of the sequence, assuming that the pattern of the first few terms continues. (Assume that $n$ begins with 1.)
$\{\frac{1}{2}, \frac{1}{4}, \frac{1}{6}, \frac{1}{8}, \frac{1}{10}, \dots\}$
$a_n = $