Project Euler 27

gistfile1.rb

require 'Prime'
max, answer = 0, 0
(-999..999).each do |a|
  Prime.each(999).to_a.each do |b|
    n = 0
    n += 1 while Prime.prime?(n ** 2 + a * n + b)
    max, answer = n, a * b if max < n
  end
end
puts answer # -59231