Tests if a number is weird.

weird.rb

class Fixnum
  def weird?
    divisors = (1..self/2+1).select{|n| self % n == 0 }
    return false if self == 2 or divisors.reduce(:+) <= self
    !(2..divisors.length-1).map{|m| divisors.combination(m).to_a }.flatten(1).any?{|a| a.reduce(:+) == self }
  end
end

70.weird?
=> true