Data.Combinatorics.Factorial:
* Various implementations
* Get direct access to the GMP version.
* Benchmarking
Data.Combinatorics.Binomial:
* Other implementations?
* Memory analysis. E.g., making sure we can replicate Luschny's memory bound for binomials.
* Talk to people re integrating HaskellForMaths, gamma, statistics, erf, math-functions, combinat, species, multiset-comb,...