- #1

Monoxdifly

MHB

- 284

- 0

\(\displaystyle \frac11+\frac1{1+2}+\frac1{1+2+3}+…+\frac1{1+2+3+…+2009}\)

Like my previous question, I believe this one also has something which can be canceled out, and the denominators contain arithmetic series. Can this series be used to make some sorts of shortcuts?