Zero-sum free sequences with small sum-set
  Let A be a zero-sum free subset of Z_n with |A|=k. We compute for k\le 7 the least possible size of the set of all subset-sums of A. 
Gautami Bhowmik (LPP), Immanuel Halupczok (DMA), Jan-Christoph   Schlage-Puchta