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<html>
<head>
  <meta charset="utf-8">
  <title>JS Number Pattern 54 - Try It</title>
</head>
<body>
  <h1>Mirrored Diagonal Number Diamond</h1>
  <p>Edit n and click Run.</p>
  <pre id="output"></pre>
  <script>
    const n = 5;
    const width = 2 * n - 1;
    let result = "";
    function buildRow(i) {
      let line = "";
      for (let col = 1; col <= width; col++) {
        const leftDiag = col === i;
        const rightDiag = col === width - i + 1;
        line += (leftDiag || rightDiag) ? String(i) : " ";
      }
      return line.trimEnd();
    }
    for (let i = 1; i <= n; i++) result += buildRow(i) + "\n";
    for (let i = n - 1; i >= 1; i--) result += buildRow(i) + "\n";
    document.getElementById("output").textContent = result;
  </script>
</body>
</html>

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JavaScript Number Pattern 54 (Try It)