The n-th birthday of a very famous mathematician coincides with a year that corresponds to the (n+1)st prime number. Who is this mathematician?
Answer: Leonhard Euler (15 April 1707-18 September 1783). His 304th birthday coincides with this year 2011, which happens to be the 305th prime number.
This puzzle was contributed by Aziz Inan, Professor of Electrical Engineering at the University of Portland. His own name, when written in capital letters, is a geometric word puzzle. Swap the vowels and turn the consonants 90 degrees and the words have switched places. "My parents didn't plan this," he says. "It's just fun."