1. Write each series using sigma notation. 2. The series is: 2 + 5 + 10 + 17 + 26 + 37 3. I know that above the sigma, the number is 6 because there are only six terms in the series. The trouble I seem to have with this is the fact that the series is neither arithmetic or geometric. It increases by consecutive odd integers. I don't know how to figure the notation for this series.