Problem
https://projecteuler.net/problem=7
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 10001st prime number?
Answer: 104743
Solution
#!/usr/bin/env ruby
require 'prime'
def find_10001_prime
sieve = Prime::EratosthenesGenerator.new
answer = 0
10_001.times { |_i| answer = sieve.next }
answer
end
puts find_10001_prime if __FILE__ == $PROGRAM_NAME