ing method 1 from
          H. Cohen, F. Rodriguez Villegas, D. Zagier, "Convergence acceleration
          of alternating series", Bonn, (1991). The result is valid everywhere,
          but doesn't always converge, or may become too divergent in the first few
          terms to sum accurately. This is used for <span class="emphasis"><em>ah &lt; 1</em></span>.
        </li>
<li class="listitem">
          A modified version of T2 which is accelerated in the same manner as T1.
          This is used for <sp