Sieve of Eratosthenes is an algorithm to find prime numbers from 2 to a given number.

Crivo de Eratóstenes

## Code
module Crivo
  def self.gera_primos(til)
    list = (2..til).to_a
    list.each do |pivot|
      list = remove_multiples(list, pivot)
    end
    list
  end

  def self.remove_multiples(list, pivot)
    list.find_all {|n| (n % pivot) != 0 || pivot.eql?(n) }
  end
end

puts Crivo.gera_primos(100)
## Output
$ ruby crivo_eratostenes.rb 
97
89
83
79
73
71
67
61
59
53
47
43
41
37
31
29
23
19
17
13
11
7
5
3
2