The definition of a sequence of real numbers is : a function from N to R. What is the standard way to handle a sequence like (1/log n) where the first term is undefined? Do we instead write (1/log (n+1)) so that the first term is defined? Or leave the first term undefined? The definition says that the function must map from N to R. So every element in N needs to have a valid image. Would undefined terms violate this definition? E.g. f(1) = (1/log 1) do not exists. What happens when we have the sequence (An/Bn) where (An) and (Bn) are two convergent sequences with non-zero limits? Some of the terms of (An/Bn) might be undefined due to Bn being 0. Do we drop just those terms or drop the initial terms until all remaining terms are defined? Thanks!