Put 2n balls in a bag, numbered 1 to 2n. Pull out half of them at random and add their values. How many different sums are possible? n outcomes 0 1 1 1 2 2 3 3 4 6 5 12 6 17 7 24 8 32 9 40 Enumeration of all KSubsets becomes hard after that. Any intelligence around? w.meeussen.vdmcc at vandemoortele.be tel +32 (0) 51 33 21 11 fax +32 (0) 51 33 21 75