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?

*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."*

*If you have a puzzle you think might interest Plus readers, please email us!*

## I wondered what sort of

I wondered what sort of coincidence and correspondence might be involved, then realized that the question simply used unnecessarily long words. Following the maxim, "Never use a long word when a short one will do," this question can be rephrased:

What famous mathematician's nth birthday falls on a year that is the (n+1)th prime number?

## Happy Birthday Euler

Euler, born 1707, would be 304 in 2011, which is the 305th prime.

## Happy Birthday Euler

Euler, born 1707, would have been 304 in 2011, which is the 305th prime number.

## by how you remember eular's birth day?..

This is amazing answer & duff to calculate the 305-th prime number

## Euler is the obvious answer (for 2011)

Let's not overlook that in 2129, it would be Évariste Galois' 318th birthday (and 2129 is the 319th prime).

Sure, Évariste Galois is listed as only the 14th most famous mathematician [1], but he died at age 20. Give him a break!

[1] http://fabpedigree.com/james/mathmen.htm

## Another solution

If we use the Taiwanese/Minguo Calender, then Paul Erdös would work too, because in 1914, he will be 1. A conversion over to the Taiwanese calender puts the year at 3, the (1+1)th, or 2nd prime. Even though he is only the 96th most famous mathematician, he has spawned numerous things such as the Erdos number and is famous enough to be put on this list:

http://fabpedigree.com/james/mathmen.htm