Ruby では、

results = [ 2 ]

( 2..12 ).each do |outer|
prime = true

( 2..outer ).each do |inner|
# 割り切れたら、素数ではない
prime = false if outer % inner == 0

if prime
results.push outer if prime
break
end
end
end

p results #=> [2, 3, 5, 7, 9, 11]