I've been given the recurrence relation $a_n = na_{n-1}+n^2a_{n-2}$ where $a_0 = 1$ and $a_1 = 1$.
I need to find $a_{1000}$.
My understanding is that this is very similar to the Fibonacci sequence. I also believe that I need to derive an explicit formula to find (And be able to express) the answer.
Unfortunately, I have zero idea how to do this and haven't found much that really helps me despite a long search.