Another update from ingydotnet^djgoku

Task/Happy-numbers/Elixir/happy-numbers.elixir

@@ -0,0 +1,27 @@
+defmodule Happy do
+  def task(num) do
+    Process.put({:happy, 1}, true)
+    Stream.iterate(1, &(&1+1))
+    |> Stream.filter(fn n -> happy?(n) end)
+    |> Enum.take(num)
+  end
+
+  defp happy?(n) do
+    sum = square_sum(n, 0)
+    val = Process.get({:happy, sum})
+    if val == nil do
+      Process.put({:happy, sum}, false)
+      val = happy?(sum)
+      Process.put({:happy, sum}, val)
+    end
+    val
+  end
+
+  defp square_sum(0, sum), do: sum
+  defp square_sum(n, sum) do
+    r = rem(n, 10)
+    square_sum(div(n, 10), sum + r*r)
+  end
+end
+
+IO.inspect Happy.task(8)