Question 7 on Project Euler reads:

By listing the first six prime numbers: 2, 3, 5, 7, 11, and 13, we can see that the 6th prime is 13.

What is the 10 001st prime number?

This was very easy to solve using my Sieve of Eratosthenes implementation. Remember that the resulting list of primes from the allprimes() function is zero-based.