Does there exist a real sequence $\{a_n\}_{n=1}^\infty$ such that $$a_na_{n+1}\ge a_{n+2}^2 +1$$for all $n\ge 1$?
Source: 2024 Korea Summer Program Practice Test Junior P6
Tags: inequalities
Does there exist a real sequence $\{a_n\}_{n=1}^\infty$ such that $$a_na_{n+1}\ge a_{n+2}^2 +1$$for all $n\ge 1$?