In proof questions, what can consecutive numbers be written as?

The question is missing context, but I will do my best. Hopefully it helps.

When trying to prove something, or in any other situation in mathematics involving text, consecutive numbers can be separated by commas, and continued with an ellipsis (...).

Examples:

Instead of writing 1, 2, 3, 4, 5, 6, 7 you can simply write 1, 2... 7. This means all natural numbers from 1 to 7, including both 1 and 7.

Writing 1, 4, 9... would mean all squares of natural numbers.

Writing 1, -1, 1, -1... would mean a never-ending sequence of 1 and -1.