Let $S(n, t) = \sum_{k = 0}^n {n \choose k} ^t$.

The task is to find asymptotic behavior of $S(n,5)$, $n \to \infty$.

Asymptotic for $S(n,0)$ and $S(n,1)$ is very simple.

For $S(n,2)$ we can use convolution for generating functions.

But, for case $n = 5$ I need help.

Thank you for any help.