Nth Prime

Instructions

Given a number n, determine what the nth prime is.

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

If your language provides methods in the standard library to deal with prime numbers, pretend they don't exist and implement them yourself.

For this exercise the following F# feature comes in handy:

• Sequences are evaluated lazily. They allows you to work with an infinite sequence of values.

Note: to help speedup calculation, you should not check numbers which you know beforehand will never be prime. For more information, see the Sieve of Eratosthenes.

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Source

A variation on Problem 7 at Project Euler