I've searched on web some exercises about closed form formula of recursive sequence, but I have not found more difficult ones. For example the majority of them ask me to find close form formula for $a_n$, so I'm wondering if there are other ones that ask me for $a_{2n}$ or something similar. Furthermore the types of exercises that I'm looking for concerns linear sequence like these:
- $a_n = 3a_{n-1} +2$
- $a_n = 2a_{n-1} + 2a_{n-2}$
Someone of you know where I can find exercises like these? Thanks.