44.rb

def pentagon
  pentagon = []
  i = 1
  loop do 
    pentagon << i * (3 * i - 1) / 2 
    pentagon.each_with_index do |item, index|
      for b in index+1..pentagon.size-1
       puts "P1 #{pentagon[index]} P2 #{pentagon[b]}" if in_penta?(pentagon[index] + pentagon[b]) && in_penta?(pentagon[b] - pentagon[index])
      end
    end
    i += 1
  end

end

private

def in_penta?(num)
  i = 1
  loop do 
    penta = i * (3 * i - 1) / 2 
    if num == penta
      return true 
    elsif penta > num
      return false
    else
      i += 1
    end
  end
end

pentagon