diff --git a/notebooks/problem0001.ipynb b/notebooks/problem0001.ipynb
index e7b8e73..6a97f09 100644
--- a/notebooks/problem0001.ipynb
+++ b/notebooks/problem0001.ipynb
@@ -33,7 +33,8 @@
     "$$(3 + 6 + 9 + \\cdots + 999) + (5 + 10 + 15 + \\cdots + 995) - (15 + 30 + 45 + \\cdots + 990) = 233168$$\n",
     "\n",
     "## Relevant sequences\n",
-    "* Triangular numbers: [A000217](https://oeis.org/A000217)"
+    "* Triangular numbers: [A000217](https://oeis.org/A000217)\n",
+    "* Multiples of 3 and/or 5: [A281746](https://oeis.org/A281746)"
    ]
   }
  ],