<h1><span>前導</span></h1><ul><li><span>只有 </span><b><strong>主對角線及其上方</strong></b><span> 有非零元素。</span></li><li><span>第 </span><code><span>0</span></code><span> 列:</span><code><span>N</span></code><span> 個元素</span></li><li><span>第 </span><code><span>1</span></code><span> 列:</span><code><span>N-1</span></code><span> 個元素</span></li><li><span>第 </span><code><span>2</span></code><span> 列:</span><code><span>N-2</span></code><span> 個元素</span></li><li><span>…</span></li><li><span>第 </span><code><span>i</span></code><span> 列:</span><code><span>N-i</span></code><span> 個元素</span></li></ul>