How to create a pattern of numbers

How to create a pattern with a relative resolution.

I want all resolution that are relative to 750x1000 which will have same aspect ratio. I can do that manually in any image software but it will take me ages to reach till 5000 x 6667 that I want to reach. Example website

https://andrew.hedges.name/experiments/aspect_ratio/

I have no knowledge of any kind for java and python but if solution exist I will learn the language enough to process it.