What's the meaning of the numbers at the end of the episode? At the end of any episode of Yahari Ore no Seishun Love Come wa Machigatteiru, some numbers appears coupled with the title and the number of the next episode (circled).



286



266



281

What's the meaning of these numbers?
Angel Beats! also did something similar, except that the numbers, prefixed by the character 'c', appear in the previews for next episode.



These are the cut numbers found in storyboards, or （絵）コンテ (e konte, from the English word continuity) in Japanese. According to Anime Production – Detailed Guide to How Anime is Made and the Talent Behind it!,


  Cuts refer to a single shot of the camera and an average TV-anime episode will usually contain around 300 cuts.


which basically matches the range of numbers that appear in both Oregairu and Angel Beats!.

To top it off, I was able to find a screenshot (click to enlarge) of a selection of Oregairu's storyboards:



Image source: http://forum.gamer.com.tw/C.php?bsn=44991&amp;snA=514



Corrections to OP's post


The circled numbers actually mark the current, not the next, episode number. See the list of titles for all episodes (scroll down to the middle).
The numbers/titles don't always appear at the end. For example, the title of episode 2


  17 ②きっと、誰しも等し並みに悩みを抱えている。


appears very early, corresponding to the 17th scene (excluding the OP and ED) in that episode.