MathJax无法使用下标和求和来呈现方程式

Question

我在我的博客中使用MathJax来渲染方程式，但它无法渲染一些具有多个下标的方程式：

$$ T_N = \sum_{n \geq 0} N^2 $$

但以下方程式效果很好：

$$ T =  \sum_{n \geq 0} N^2 $$

$$ T_N = \sum N^2 $$

这是我的配置：

<script type="text/x-mathjax-config">
  MathJax.Hub.Config({
    tex2jax: {
      inlineMath: [ ['$','$'], ["\\(","\\)"] ],
      processEscapes: true
    }
  });
</script>

<script type="text/x-mathjax-config">
    MathJax.Hub.Config({
      tex2jax: {
        skipTags: ['script', 'noscript', 'style', 'textarea', 'pre', 'code']
      }

    });
    MathJax.Hub.Config({TeX: {
      Macros: {
         fi:    "{f\\,\\!_i}",        <!-- static f sub i, spread: \fi -->
         SS:    ["{#1\\:\\!_#2}",2],  <!-- 2-parms, variable and subscript, spread: \SS{f}{i} -->
         SUBx:  ["{\\:\\!_#1}",1],    <!-- Spread variable and its subscript: \SUBx{i} -->
         EXPx:  ["{\\;\\!^#1}",1],    <!-- Spread variable and its exponent: \EXPx{2} -->

         Ss:    ["{#1\\,\\!_#2}",2],  <!--Same as SS, less spread: \Ss{f}{i} -->
         subx:  ["{\\,\\!_#1}",1]     <!--Same as SUBx, less spread: \subx{i} -->
      }
   }
   });
</script>

<script type="text/x-mathjax-config">
    MathJax.Hub.Queue(function() {
        var all = MathJax.Hub.getAllJax(), i;
        for(i=0; i < all.length; i += 1) {
            all[i].SourceElement().parentNode.className += ' has-jax';
        }
    });
</script>

<script type="text/javascript" src="http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML">
</script>