Question 98
Sequence $(a_n)$ is defined as follows:
$$
a_1 = 1,\ a_2 = 2,\ a_{n+2} = (n+1)(a_n + a_{n+1})
$$
for each natural $n$. How many zeros does $a_{2011}$ end with?
$$
a_1 = 1,\ a_2 = 2,\ a_{n+2} = (n+1)(a_n + a_{n+1})
$$
for each natural $n$. How many zeros does $a_{2011}$ end with?