"The prolific 17th century mathematician Leonhard Euler" should be "18th century" since he lived from 1707 to 1783. "The 18th cenury mathematician Bernhard Riemann" should be "19th century".

## Off by one errors in centuries for Euler and Riemann

"The prolific 17th century mathematician Leonhard Euler" should be "18th century" since he lived from 1707 to 1783. "The 18th cenury mathematician Bernhard Riemann" should be "19th century".