A summing problem

hi, there is a positive integer n and i am trying to device an algorithm that gives me all the possible summation combinations. For e.g. n=4 1+3=4 2+2=4 1+1+1+1=4 1+2+1=4 The ordering is not important. Hence there are 4 possible summation combinations. All attempts to make an algorithm gives exponential time solutions. Is there a polynomial time solution to it? Given n, is there a formula that would count all its existing summations? Thank you, Sarad. ____________________________________________________________________________________ Looking for last minute shopping deals? Find them fast with Yahoo! Search. http://tools.search.yahoo.com/newsearch/category.php?category=shopping