This article features some genuine Eulerian magic. In 1748, Leonhard Euler considered a modification of the harmonic series in which negative signs were attached to various terms by a rule that was far from self-evident. With his accustomed flair, he determined its sum, and the result was utterly improbable. There are a few occasions in mathematics when the term “breathtaking” is not too strong. This is one of them.
Euleriana: 1(2), pp.172-180.
Available at: https://scholarlycommons.pacific.edu/euleriana/vol1/iss2/5