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<html>
<head>
  <meta charset="utf-8">
  <title>JS Number Pattern 37 - Try It (User Input)</title>
</head>
<body>
  <h1>Palindrome Number Triangle (User Input)</h1>
  <p>Enter rows when prompted, then click Run.</p>
  <pre id="output"></pre>
  <script>
    const rowsInput = prompt("Enter rows:");
    const rows = parseInt(rowsInput, 10);
    let result = "";

    if (!Number.isFinite(rows) || rows < 1) {
      result = "Please enter a positive integer.";
    } else {
      for (let i = 1; i <= rows; i++) {
        let line = "";
        for (let j = i; j >= 2; j--) {
          line += j;
        }
        for (let j = 1; j <= i; j++) {
          line += j;
        }
        result += line + "\n";
      }
    }

    document.getElementById("output").textContent = result;
  </script>
</body>
</html>

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JavaScript Number Pattern 37 (Try It — User Input)