This is a spinoff of sequential_nmbrs. Here you will find all the numbers that didn`t make it - either they were uploaded too late (or never because they have been there already) or they were not rule-compliant. They do not have to be in sequential order or unique, just numbers. And if you have a nice story to go with the picture, feel free to add it to the image description.
The group's theme changes every two weeks. You'll find it in the "title" of the Group's page. Check in often!