Finding explicit formula for recurrence relation?

Question

What would a explicit formula for this sequence? a_k = a_(k-1)/k? The way I find explicit formula is to write out some terms but this time it's not working.. I'd appreciate your help!

Answer 1

$$a_k=\frac{a_{k-1}}{k}=\frac{a_{k-2}}{k(k-1)}=......=\frac{a_1}{k!}$$