add some more detail

notebooks/problem0093.ipynb

@@ -97,6 +97,44 @@
     "\n",
     "max(combinations(range(0, 10), 4), key=streak)"
    ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "eda00caf",
+   "metadata": {},
+   "source": [
+    "Under the problem's rules, these numbers can form all the positive integers up to 51."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "id": "735dab1c",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "51"
+      ]
+     },
+     "execution_count": 3,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "streak((1,2,5,8))"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "e56a1679",
+   "metadata": {},
+   "source": [
+    "## Relevant sequences\n",
+    "* Catalan numbers: [A000108](https://oeis.org/A000108)"
+   ]
   }
  ],
  "metadata": {