The NFCONE software implements the calculations presented in Anderson, EC and Slatkin, M (2007) Estimation of the number of individuals founding colonized populations. Evolution 61:972-983. This software package contains two separate programs:
coalit: a Monte Carlo simulation program for approximating the probability that a certain number of lineages remain after a set number of generations in a discrete-time coalescent, or a certain amount of scaled time in a continuous time coalescent. nfcone: the program that implements the importance sampling scheme to compute the likelihood for the number of founders.
Output from coalit may be used as input to nfcone. I have kept the programs separate to provide more flexibility. It does mean that if you want to use this software, there are several steps and you will want to get comfortable with a command line interface to use the programs to their full potential.
RELEVANT LINKS
coalit and nfcone. Be sure to read the tutorial (link below) on how to use these.