Question 92
Define a sequence by
$$a_1=1,\quad a_2=5,\quad a_n=\frac{a_{n-1}^2+4}{a_{n-2}}\quad(n\ge3).$$
Prove that every term is an integer and find an explicit formula for $a_n$.
$$a_1=1,\quad a_2=5,\quad a_n=\frac{a_{n-1}^2+4}{a_{n-2}}\quad(n\ge3).$$
Prove that every term is an integer and find an explicit formula for $a_n$.