defmodule RecreationOne do
  def list_squared(m, n) do
    res = Enum.map m..n, fn(a) ->
      sum = sum_squared_divs a
      rooted = :math.sqrt sum

      if :erlang.trunc(rooted) == rooted do
        { a , sum }
      else
        0
      end
    end

    Enum.reject res, fn(a) ->
      a == 0
    end
  end

  def sum_squared_divs(a) do
    divs_squared = for b <- 1..a, rem(a, b) == 0 do
      :math.pow b, 2
    end

    Enum.sum divs_squared
  end
end