Not 100% if this is what you are looking for, but maybe Reduce("+", x) will do it? E.g. Reduce("+", 1/2^(1:10)) # [1] 0.9990234 Hope this helps. Allan On 14/07/10 11:57, David Bickel wrote: > What are some reliable R functions that can compute the value of a > convergent series? > > David >