# Take number and return unique factors as a sorted list

def factor(n)
  f = []
  1.upto(Math.sqrt(n)) do |i|
    if i == 1
      f.push(i)
    elsif n % i == 0
      f.push(n/i)
      f.push(i)
    end
  end
  f.push(n)
  return f.uniq.sort
end