Hiroki and Mapiya were asked to find an explicit formula for the sequence $125\,,\,25\,,\,5\,,\,1,...$. Hiroki said the formula is $f(n)=625\cdot\left(\dfrac{1}{5}\right)^{\large{n}}$, and Mapiya said the formula is $f(n)=125\cdot\left(\dfrac{1}{5}\right)^{\large{n}}$. **Which one of them is right?** [[☃ radio 1]]