Hi, several months ago I had a similar problem, but it was actually not resolved. I added the present letter to the former thread, but it did not appear in the dashboard, so that I am writing it as a new question. I need to obtain series expansions of several functions, and it seems that while obtaining a few terms (let's say up to 20) does not present a problem for MATHEMATICA, a request to produce merely 40 terms causes the program to work continuously for more than two days without a perspective to finish soon. The limit of time for a single job, available for me, is 72 hours, so I need to do SOMETHING to reduce this cost. One example is the series: F[z_]=(1+z+zth)/(2z((Sqrt[1+z]+Sqrt[z]th)^2)); Series[F[z],{z,∞,40}]; where "th" is a positive parameter. My question is: is there any way to split the calculation process into two or more runs? I presume this would require saving somehow the intermediate results generated by Series[] and read them in in the next run(s). Would this be possible? Or, is there any way of combining the Series[] command somehow with other commands like Simplify[] in such a way so that the intermediate results are simplified before they are subject to further processing? This might reduce the (supposedly exponential) growth of the intermediate results. Or, is there any other method of speeding the calculations that might be applied in this case? Or, as a last resort, is there any method to stop prematurely the execution of Series[] just before the time limit is exhaused, so that I can at least save the terms that were effectively obtained during the three days of calulations, instead of wasting these three days without obtaining anything? Leslaw