Preheat oven to 375 degrees. Flour and grease baking pan. In a large bowl mix together cake mix, pudding mix, oil, water and eggs. Prepare the Streusel by mixing together the flour, sugar, cinnamon, and melted butter. Put 1/3 cake mix in the 9 by 13 inch cake pan, then add 1/2 of the topping. Add the remaining cake batter and then top with the streusel mix. Bake for 30 – 35 minutes or until done.