An interpretation of Motzkin numbers, the 21 paths from (0, 0) to (5, 0) using only steps northeast, east, and southeast, never dipping below the x-axis.
<a href="//commons.wikimedia.org/wiki/User:Mrmw" title="User:Mrmw">Mrmw</a>
Own work based on: <a href="//commons.wikimedia.org/wiki/File:Motzkin5.jpg" title="File:Motzkin5.jpg">Motzkin5.jpg</a>: <a href="//commons.wikimedia.org/wiki/File:Motzkin5.jpg" class="image"><img alt="Motzkin5.jpg" src="https://upload.wikimedia.org/wikipedia/commons/thumb/c/ca/Motzkin5.jpg/80px-Motzkin5.jpg" decoding="async" width="80" height="25" srcset="https://upload.wikimedia.org/wikipedia/commons/thumb/c/ca/Motzkin5.jpg/120px-Motzkin5.jpg 1.5x, https://upload.wikimedia.org/wikipedia/commons/thumb/c/ca/Motzkin5.jpg/160px-Motzkin5.jpg 2x" data-file-width="1313" data-file-height="411"></a>