I tried to render a math block with triple ticks to Github page.

```math
E = m c^2
```

The reason to use those triple backticks (instead of $$) is that they work best in Markdown preview.

But the equation is not rendered on the GH page, although I already set the _includes/head-custom.html as follows (called in _layouts/defaults.html). I used the default primer theme from GH pages.

<script type="text/javascript" id="MathJax-script" async
  src="@3/es5/tex-mml-chtml.js">
  </script>

<script>
  MathJax = {
    tex: {
      inlineMath: [['$', '$'], ['$`', '`$'], ['\\(', '\\)']],
      displayMath: [['```math', '```'], ['$$', '$$'], ['\\[', '\\]']]
    }
  };
</script>