What is the computer program that attempts to simplify sums of binomial coefficients, factorials, etc.? Possibly Zeilberger wrote it, but I'm unsure. If so, possibly it was talked about in his A=B book. I vaguely remember these things, but my google searches have not produced anything, so I'm unsure.
Thanks!
Edit: I aim to simplify expressions like
$\sum_{s=0}^k {n-l \choose s} {l \choose k,k-2,l-2k+s}\cdot k! \cdot 2^{s-k}$
I have also already checked through math.rutgers.edu/~zeilberg/programs.html. Does the program EKHAD attempt to simplify such expressions?