diff --git a/ipynb/Golomb-Puzzle.ipynb b/ipynb/Golomb-Puzzle.ipynb
index 4fb3021..5f55b59 100644
--- a/ipynb/Golomb-Puzzle.ipynb
+++ b/ipynb/Golomb-Puzzle.ipynb
@@ -61,7 +61,7 @@
     "> 9 × 7 × 5 × 3 × 1 = 945.\n",
     "\n",
     "(It is always a relief when two methods give the same answer.)\n",
-    "          \n",
+    "\n",
     "**Method 3: Write a program to enumerate the sets:** We'll represent the 1 × 3 rectangle as the tuple `(1, 3)` and the example set of rectangles as the set\n",
     "\n",
     "    {(1, 3), (2, 4), (5, 7), (6, 8), (9, 10)}\n",