```Date: Feb 24, 2012 6:09 AM
Author: hardya
Subject: Advanced Permutations software

I am new to maths, but I think I know the basics.  I am looking for some permutations software.Amongst other things I want to know a permutation like this:250 distinct locations.  At each location there may be an object of type A or type B.  So I can say 2 to choose from, number chosen 250, order important, repetition allowed and I get 1.80925139e+75.However I know the ratio of A and B type objects is fixed, 30 A 220 B.  I could say I have 250 distinct objects (already knowing for each if it is A or B) and just work out the combinations of locations, so n=250, r=250, order important, repeats no and get 3.23285626e+492.  However I am not really bothred about the individual obejcts just the type at the location so many of these combinations would be for my purposes the same.So I want to find the number of combinations for any 30 A 220 B distributed around 250 locations.  And I may have a few other similar things like this.  So I am looking for some dedicated software which may help me to obtain these results and perhaps identify the relevant equations, however most of the stuff I have seen so far only allow the basic parameters n, r, order?, repeat?.  Does any one know of any software that would help me to do more complex cases such as the one I have suggested?Once I have got over that hurdle, I may want to think about ways to justify selecting a particular subset of such combinations/permutations as a valid sample.Any help or advice in this area would be greatly appreciated.Message was edited by: Andrew Hardy
```