A WebmasterWorld thread has some webmasters claiming Google is randomizing the number of search results displayed on the Google search results.
Google typically and by default will show 10 search results per page. But these users are claiming that sometimes Google will show 10 results, sometimes more than 10 and sometimes as few as no results! This happens for the same search result set but changes based on which page of results you click on. I personally cannot replicate it.
Here is what the webmaster said:
For a SERP initially reporting nearly 400 results, there's links to 19 pages of results along the bottom of the page.
Clicking through this initial search reveals only 11 pages before running into the usual "omitted similar pages" Duplicate Content warning.
After clicking this "show all results" link, there's 10 results on each of the first five pages.
At this point there are links to 19 pages of results along the bottom of the screen. So far so good.
Page 6 has only 6 results.
Page 7 has 10 results.
Page 8 has zero results.
At this point there are links to 17 pages of results along the bottom of the screen.
Page 9 has only 4 results.
Page 10 has only 3 results.
Page 11 has only 9 results.
Page 12 has 10 results.
Page 13 has only 9 results.
At this point there are links to 18 pages of results along the bottom of the screen.
Page 14 has 10 results.
Page 15 has only 7 results.
Page 16 has only one result.
Page 17 has zero results.
Page 18 has zero results.
After this there are no more links to further results.
Wild, no? Bug? Maybe? Weird Google test? Maybe?
Forum discussion at WebmasterWorld.