I am doing some problems in sigma notation and two of them have come up with an ERR: INVALID DIM on my calculator screen, the problems were as follows: lower limit = 1, upper limit 1000 and index of summation 1/n, the other one had lower limit = 1 and upper limit = 5000 and index of summation 1/n. Are these sums considered finite? Why?

Thank you,

Keith Stevens