Problem 1696 (difficulty: 5/10)

\(\displaystyle \sum_{k=0}^\infty \frac1{k^2+k+1} = ? \)

(The result should not contain any complex number!)

Give me another random problem!

Subject, section:
Requested difficulty:
Request for a concrete problem:I want problem no.

Supported by the Higher Education Restructuring Fund allocated to ELTE by the Hungarian Government