copy of realjenius bit of non-plugin liquid code to generate a series of posts https://github.com/realjenius/site-samples/blob/master/2012-11-03-jekyll-series-list/series.html

jekyll-liquid-series-list

{% assign count = '0' %}
{% assign idx = '0' %}
{% for post in site.posts reversed %}
	{% if post.series == page.series %}
		{% capture count %}{{ count | plus: '1' }}{% endcapture %}
		{% if post.url == page.url %}
			{% capture idx %}{{count}}{% endcapture %}
		{% endif %}
	{% endif %}
{% endfor %}

<div class="seriesNote">
	<p>This article is <strong>Part {{ idx }}</strong> in a <strong>{{ count }}-Part</strong> Series: "{{ page.series}}"</p>
	<ul>
	{% assign count = '0' %}
	{% for post in site.posts reversed %}
	{% if post.series == page.series %}
		{% capture count %}{{ count | plus: '1' }}{% endcapture %}
		<li>Part {{ count }} - 
		{% if page.url == post.url %}
			This Article
		{% else %}
			<a href="{{post.url}}">{{post.title}}</a>
		{% endif %}
		</li>
	{% endif %}
	{% endfor %}
	</ul>
</div>