  A_k = {1, a_2, ... a_k} is an h-basis for n if every positive integer not
exceeding n can be expressed as the sum of no more than h values a_i. An
extremal h-basis A_k is one for which n is as large as possible. Computing
extremal bases has become known as the Postage Stamp Problem.
  This paper is inspired by and based upon a paper entitled "Symmetric bases
with large 2-range for k<=75" by Svein Mossige at the University of Bergen
(Mossige, Svein, [4]). Computer searches have identified some further bases
which are superior to those reported in [4], and the paper also reports an
improvement to one of the theoretical results.
