# File lib/backports/1.9.1/stdlib/prime.rb, line 425
    def initialize
      @primes = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101]
      # @max_checked must be an even number
      @max_checked = @primes.last + 1
    end