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<html>
<head>
  <meta charset="utf-8">
  <title>JS Number Pattern 55 - Try It (Browser)</title>
</head>
<body>
  <h1>Column-Wise Filled Number Triangle (aligned cells)</h1>
  <p>Edit n and click Run.</p>

  <script>
    var n = 5;
    var tri = Array.from({ length: n }, function () { return []; });
    var value = 1;

    for (var col = 1; col <= n; col++) {
      for (var row = col; row <= n; row++) {
        tri[row - 1][col - 1] = value++;
      }
    }

    for (var r = 1; r <= n; r++) {
      for (var c = 1; c <= r; c++) {
        document.write('<span style="display:inline-block;width:3em;text-align:right">' + tri[r - 1][c - 1] + '</span>');
      }
      document.write("<br>");
    }
  </script>
</body>
</html>

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JavaScript Number Pattern 55 (Try It — Browser)